Well, I like your ambition =) My best advice is don't try to tackle it all at once for a few reasons. It's not cheap and do it right the first time =)
Determine your goals for the truck. Do you want it as a Daily Driver? Something you can cruise on the highway long distances or something purely offroad?
There are tons of ways you can solid axle swap these rigs and a lot of people will argue the best way. I don't half ass anything anymore, it's always come back to bite me in the butt so I just save up the cash to do it right the first time or go without.
check out www.allprooffroad.com www.marlincrawler.com www.trail-gear.com
for SAS kits, all good ones.
and 5" lifts is excessive, might consider 3" with 33's for practicality, but a million people will argue otherwise. But I think it's safe to say everyone will agree low and stable is best.
and you're gonna need to think about rebuilding that v6 sooner than you probably want to. 240k on that motor is A LOT. =) Also, rear axle rebuild, brake upgrades, front wheel bearings... the fix it list goes on and on with these old trucks.
It's not uncommon or above average or excessive to say most people easily dump 10k$ into their rigs. This stuff aint cheap, it adds up stupidly fast. I've dumped about $1500 i think into mine this year. And thats just maintnence, new head/cam engine stuff, other crap. about 2 grand in the rear axle alone.
bottom line have fun and be safe! =)