just got truck and i have some questions.

[Galidah]

well.. today i just bought my first truck.
its a 1970 GMC custom camper.. i think its a 1970?
i got it for $400.. the engine is solid, sturdy and powerful..
the body.. has seen better days. everything is decent rust-wise 'cept for the hood, which looks like formed rust.. fixable but i almost think i'd rather replace it.
the only other major problem is the floor in the cab.. its got two rusted holes that you can see through, which are kinda big.. about 3in diameter..

tonight i spent some time taking apart the dash to replace the hoses for the vents.. cus they were all destroyed from age.. but i did the stupid thing of not remembering how to put them back in.. that shouldnt be hard though.

i was just wondering the basic questions..
what are the first things i should check, fix, replace, modify.. etc..
what are the best sites/places for parts..

where would i start on fixing that floorboard.. i'm wanting to get one of those rubber mat's that cover the entire floor.. so i might just do a quick fix..

i'm not shooting for restoration quality.. i just wanna make it so its decent quality again.