Plenty of time to do your homework mate and maybe organise taking someone along with you for a second set of eyes.
Try and get it on a ramp, this is a must so you can check the chassis front to back, it's a ladder chassis and most of it is on show, front legs should be fine as oil leaks protect them, under the front and rear doors are the outriggers, you'll see them coming off the chassis like supports, get a screwdriver behind and poke about, gentle like, inside the outriggers is the gearbox cross member, they rot behind where it's fixed so check around the fixings for any signs.
At the rear behind and around the fuel tank they go as crap gets stuck around it but the rear part of the chassis is replaceable if it's just that.
Talking of oil leaks they leak from everywhere, they did from new but minor not excessive, a full seal kit for the engine cost me about £17 so no problem just labour costs.
Check where the battery sits in the seat box under passenger seat, a new seat box is £££££££ so if it's rotten it will need work or replacement, my battery was sat on a fibreglass base and the battery was falling out.
Take a magnet and stick it on the corners of the bulkhead at the corners of the windscreen, if it's filler it's probably rotten elsewhere.
Just a few things to look for but these are the most important and could cost big bucks to put right.