DaveO,
Yeah, as TerryS mentions, the rust can be the terminal problem for some of these trucks...however, being as you're in the UK, replacement pieces should be pretty easy to come by...well, except for the firewall or bulkhead. You *have* to weld new door posts and footwells in there for a proper repair. Mine took 40 hours of welding work to get back together...so if you can't do that yourself, it's a major expense.
Also, if you can find a diesel or an LPG conversion, that would be better for your wallet, my truck hasn't ever done better than 17mpg.
Everything else is pretty easy to fix on these trucks...There really shouldn't be any smoke out the tailpipe or sloppy steering...
Bogatyr