having a trd will not make any difference in the snow. The main plus to a trd is the diff lock (among other things), which you dont want in the snow anyway. Winter tires are not even really nessisary on a 4x4 truck like they are on a car, just good off road tires. Being a compact truck, some weight in the back cant hurt and will give you more traction, but again having 4x4 of course usually takes care of the traction issues. 1st gens are famous for being bullet proof and being goddam tanks. Arguably the best off road trucks you can get. small, nimble, usually enough power, indestructible drive train system, easily modifiable. The earlier 1st gens did have frame problems but they are still well under warranty. If you live in a state that uses salt defiantly have it checked for frame rust from a dealer. If not, still have it checked. They will either buy back the truck, or replace the frame. I believe they will only buy it back at market value if you have only owned it for more than 2 years, if not they will fix the rust/replace the frame/or spray on a protective under coating free of charge. Tacomas are some kick ass, super dependable, super capable, trucks and it takes a whole hell of alot to break the brand loyalty these trucks (especially the 1st gens) have gathered.
these are some sought after trucks...so they will cost a pretty penny for being 9-11 years old. If you are looking for a 2000 ext cab 4x4 non trd around 150k, which is the average, 7500-8000 is a pretty good deal. If you get one, there is a 99% chance you will love it do death and be extremely, extreamly happy with it.
check out tacomaworld.com, there are a shit load of 2nd gens, but still more tacoma info than you will ever need. Happy truck hunting