If you're low level, then yes, do everything yourself. But once you start getting up there, you begin to realize how futile it is.
The amount of experience you need for a level double about every 7 levels. I can give you the exact formula is you want. But think about it this way, level 92 is only half way to level 99. Level 85 is only 1/4 of the way there. Level 78 is only 1/8 of the way there. Level 71 is only 1/16 of the way there. At level 64, which is what you said your mining is at, that's only 1/32 of the way there. Now think how long it took you to get that high. Now multiply that by 32. Now consider there are 23 skills (last time I checked). Assuming all skills are equally easy to train, which they're not, then getting one skill to level 64 is about 1/736 of the effort you'd need to get all your skills maxed out. If you did that in 1 day, then you're looking at a little over 2 years to get the rest of your stats up. If it took you a month, well, then it's a little over 61 years.
Now stop and think for a minute about how these games make money.
Anyways, from person experience, I say it's not feasible to do everything yourself. I know because I tried trading to reduce the time needed to get what I wanted to train with. I also considered the cost of trading, and you're still not only making money, but you end up making money at a faster rate. It's like making 20% on 1 million, instead of 100% on only 100000. Here's is the kind of stats I had when I stopped playing:
... (6 skills below 1 mil xp (about lvl 73) that I don't feel like typing)
Construction 52 (lowest)
I'll tell you right now, that I didn't collect all the materials I needed by myself. For the fletching, I made a little over 73600 yew bows. I bought the flax, and I bought the wood. I turned all the flax into bowstring myself, I cut all the logs, and I strung all the bows. I was in the process of high alching them all when I quit. I bought the nature runes for that too, although I might have only stocked enough for half of them at the time, I can't remember now. Think how long that would take if I collected the flax and logs myself. The flax, maybe somewhat doable. But the logs would have just been crazy.
Also, it's way more convenient to make laws than it is to make nature runes. Much faster, completely safe, more experience per essence, and they're worth more on the market. You can potentially make nature runes just as fast if you go through the abyss, but then you open yourself up to getting PKed, and you'll be skulled and likely risking a glory ammy, and a lot of trouble. Any safer way is slower. The only exception is if you're over level 91 rune crafting (which very few people are), and you can get double nats, in which case get some runners that essentially pay you. Now think about this. You can make the same number of law runes in less time, in a completely safe way, for more experience, and sell them on the market for the usual price of about 350 each, and then buy the nature runes you need at 310 each, thus saving time and making a profit. If you're below level 91, but above level 54 so you can make laws, the choice about which way is better is pretty clear. The only real downside to making the laws and trading for nats, is having to trade. Yes, there are some dumb people out there you might run into while trading. Just ignore them and think about how much time and money you're saving.
I have made over 3 mil gp in a day by selling law runes, and that's if you include the cost of the essence which I bought (way back when it was cheaper and more plentiful, although the deal is still pretty good).
Then think about smithing. It's almost hopeless on the free world. You can never really make a consistent income off of it. If you want to train it there, it's pretty much guaranteed money lost. But as a member, the money is mainly in iron throwing knives, and steel cannon balls. Maybe a bit in iron arrows too. You might occasionally get a sweet deal on another oddity, but don't count on it. Don't expect a steady income selling suits of armour. Sure you can make quite a bit on each deal, but a person only really needs 1 set, so the deals end up being smaller overall and harder to come by. Plus the people you end up dealing with are inevitably more annoying. The real money is in disposable goods, which there is always a large market for. No matter how many are out there, people can always make use of more. (i.e. arrows and throwing knives). Now consider how much mining xp you get compared to the smiting experience for what you mined. You'll have low smithing no matter what you mine if you're not buying. There's just no way to keep your smithing as high as mining without supplementing it somehow.
If you're a member you can train smithing at a profit though. If you buy iron ore at around 110 each, which seems to be the standard price, and get some rings of forging so you get 100% smelt rate then you almost double your money selling iron knives at about 40 each, which is a very common price last time I checked. The rings last for 140 ore, so even if you buy them at 5000 each, that's still only 5000/140 = 36 gp per ore. That about 146 gp spent per ore if you buy everything. If you're selling iron knives at 40 each, and get 5 per bar, that's 200 gp per bar. You still making at least 54 gp per ore, and even if the prive of the knives drops to 35 each, you still making over half that. I've seen the price go as high as 45 or even 50 once. Don't count on that though, and don't resort to 35 unless you've failed to sell for an entire day or two. Also, as a member, with a glory ammy, it's very easy to come by gems. I usually had 800 to 1000 rings of forging stocked at any given time, so I never needed to buy them, thus increasing the profit (to almost half).
Iron arrows are a bit more deceptive. You can get 15 arrow heads per bar, but you also need feathers and arrow shafts to use them. The feathers are easy to come by, but the shafts are somewhat more rare. I've gotten in a number of debates with CK9 about just how long it takes to make your own shafts. He seems to be very much of the mind of doing everything yourself. Shafts do seem easy, and I sometimes try to make a few on my way between places, but really they are too slow going to make enough to get a reasonable amount of arrows to sell. Typical trades I made were almost always over 100k gp, and usually much more. It takes a significant amount of a day to make enough shafts to sell 100k gp worth of iron arrows. If that's all I did in a day, I'm thinking maybe that could (partially contribute) to about 300k gp worth of produce to sell in a day. Considering I can make 10x more gp per day with law runes, this isn't a very good use of my time. If you buy both the feathers and arrows, as well as the ore and rings of forging, then it costs around 12 gp per arrow for feathers and shafts (this cost can easily vary between 8 and 20 gp per arrow), times 15 arrows in a bundle, plus the cost of the ore to make the 15 arrow heads, that's about 326 gp per bundle. If you're selling iron arrows at about 25 each, that's about 375 gp per bundle. So in this case the profit per iron bar processed is slightly less than throwing knives, but the time is a lot greater since you still have to put the arrows together. Granted you do get a bit of fletching xp, but making bows was a much faster and more profitable way of doing that anyways. I basically only made arrows when I was doing other things like agility training. That way it helps hide the time to make the arrows, since you're doing not much else with a mostly empty inventory anyways for long periods of time.
Basically, if it's not worth doing in bulk, then it's not worth doing. Basically if you can't easily get someone else to buy lots of it, and if you can't high alch it for a profit, don't waste time making it. Also, don't waste time collecting resources that don't get you a good rate of xp, (or any xp in the case of things like flax), since you can easily make more in a day selling produce even after paying someone else to collect it. It's a waste of your valuable time.