Right, what you really need is a bit of a project list, and this is the order I'd worry about things......
1) Check what you really have - rear suspension wishbones, front suspension wishbones and where they attach to the chassis...... then whip out the seats, carpet and underfelt (soggy underfelt straight into the bin!) so you can inspect the outriggers. - there are threads on here, and videos on YouTube on methods to repair them, and as Jim says, anyone who can use a welder can fix it (time/labour is the cost, not materials, which is all just 1.6mm steel sheet). I've done a few, and the last one (for a member on here) took a day to do each side, interspersed with drinking tea, having a fag break and eating!
2) Decide if you have a viable project or not...... I would presume that the previous owner decided it wasn't for him/her, but that doesn't mean it is beyond all help - I've rescued all sorts in the past. Be realistic at this point, otherwise you can set yourself up for a lot of grief. Some parts you need are cheap, some are dear, some are not available and will need to be fettled and fashioned in an ingenious way. It does appear that the PO has "asset-stripped" it a bit by removing the rear lights and the correct wheels - but this isn't a complete loss.
3) If it is beyond your wishes/ability/pocket then now is a good time to get shot.... before you fall in love and then all is lost to long days in a garage with Radio 2 a set of tools and a mug of tea for company (We've all been there!!!)
4) Whilst the obvious desire is to get out on the road with it, approaching in a logical way is always good....
5) Fix the outriggers first - they can't be seen and will be a real confidence boost and impetus to continue once done...... no special parts are needed.
6) If the suspension wishbones are okay, they need to be cleaned, de-rusted and painted....... if not, they need to be cleaned, de-rusted, repaired and painted (or replaced), At this point, replacement of bushes and balljoints is a good idea, but if time/money is against you, just do what you need for now.
7) Brake system is easy to overhaul, or you can just go straight for an 'upgrade' in callipers/disks from PNM (Using Hi-Spec callipers).... others will tell you to do that anyway, I say do what you are happy with, have the confidence to do correctly, and wish to pay for.... loads of info on the forum about both options, and various "offshoot" projects around the brake system.

Alll the time keep looking for those hard-to-find items like light units and seals, or decide how you are going to do something different......
9) ALWAYS ask questions about things you wish to do, or parts you need..... someone on here will have already had to do it, and if they can't help, they can commiserate with you! Don't just pay out for parts without researching (or asking!) as many are quite cheap generic or 'parts-bin' items. Obviously, many are bespoke, but there may be an alternative, so ask.
Oh, and with the door, is it the lock that won't undo, the actual mechanism that won't unlatch, or the hinges rusted shut??? - either way, removal of the door card may be necessary to access the mechanism, or the hinges can be accessed from the drivers' side A post (down by the bonnet release) and unbolted from there if it is that end which is the problem.....