You coul dbe fine driving it for a while, after my burnt valve was diagnosed the last time I drove it for about another 300 miles while I debated rebuilding it myself, paying a shop, or doing the 3.4 swap. I think as long as you are conservative with the mileage you should be o.k. for a while.
Depending on your height you should be able to do remove the top end(not the heades), withoput have to stoop. I myself have 4 hurniated discs in my lower back and was able to removeeverything off the engine except for the heads, those SOB's are heavy if you have a bad back, definately get help with those.
As Rousch mentioned pull the cam gears wioth theheads still attatched to theengine. You will need a large wrench, about 1-1/4 IIRC, and a 2x4 cut at about 18", for the passenger side cam place the 2x4 on the uper A-arm to brace the wrench, for the driver side the 2x4 rests on top of the engine. The other PITA is the removing the crankshaft pulley, I tried using the engine comp. trick, but I couldn't brake ity loose, so I made my own crank shaft holding bar.
With the tear down just pace yourself and you should be o.k., I tried following the manual in steps, but not knowing what each part was by name, I found it eaiser to simply remove and lable the parts as I went. Another trick that is helpful is to use cardboard to put the bolts in, this way I kept them in the order they came out with the part. The tear down went slow doing the extra work, but it made the rebuild a snap, even though it was about 6 weeks from tear down to rebuild, tore my knee up just after pulling the engine down.
My Downey headers were cheaper ordrering them from Central-4wd, than they were from Downey by about $50., I believe they were $360. You will need to order the x-over kit runs about $135, you can build your own, or see what a shop will charge. If you do build your own, have some flanges welded to the headers, once you have tightened the clamp down on them they are hell to get back off.
