renovating Trek 400 bike
Hi, I found my dad's old 1992 Trek 400 in the attic at their place and was wondering if there is a cost-effective way to get it rideable again (I think I tried riding it like 10 years ago briefly, and before that it hadn't really been ridden for another 10 years or so). I will be visiting them in the summer for a short period of time so I wanted to do all the legwork/get parts/etc. so in the brief time I have there I can just bring everything to a LBS, especially since the area is very high cost so I don't want to have to buy the stuff at the LBS.
I grabbed a picture from the 1992 trek catalogue I found online with all the specs and attached it here.
So questions for all you experts:
1. I'm a big guy (6'8", close to 300 lbs), so those narrow tires definitely won't cut it. Can I replace the tires with something wider or would I have to get all new rims?
2. If I do get all new rims, what's the widest I can fit on this bike? If someone could just identify the general sizes and types that are compatible I can search myself, but I really don't know anything about bike mechanics.
3. Alternately, if you have any recommendations for something very inexpensive (and I mean regular person inexpensive, not bike afficionado inexpensive)? I am only interested in cost and strength in that order, performance and weight are completely irrelevant to me. Also, yes, this bike may be a little small on me frame-wise but it is either this or nothing.
4. Will the bike need a new chain? It's been inside the entire time, but it also hasn't been maintained. If so is there a specific size/type I need? Any recommendations? Again, strength and cost are my only considerations.