Firstly if your going to own a Disco 1 and you want to actually have money at any point in your life you will need to buy a Haynes manual, keep your membership to this forum, learn basic landy maintainance/mechanics and ideally buy a welder and learn to weld. A huge amount of spare time, determination, patience and stubborness not to walk away from a job will also go a long way, you really have to be dedicated to own a Landy, they need more maintainance than a car and they tend to break, a lot.
Rust is a big problem on discos, the floor mainly but also the roof and chassis, usual places are the sills, boot floor, inner front wings, inner and outer rear wings, bulkhead, check the chassis, the rear cross member, pull the carpets up and check for wetness, feel the headliner to see if its damp. Also check the condition of the headlamp boxes and battery tray for tin worm.
Most of the seals can fail so check for leaks underneath and also check the sunroof and windows.
If the rover V8 has been looked after well and serviced regulary hopefully you should be ok, check its service history, also have a quick read through this it may help a little:
RPi Engineering - V8 Engines
With regards to making the experience more "fun" I find a good stainless exhaust system on a V8 brings a smile to my face every time.
Theres probably lots more that ive forgot (ive only just got up and not had my coffee yet!) but others will come along shortly and fill in the gaps.
In the mean time hope this helps.