I have done 2 head gasket and 1 engine rebuild on 3.4 4runners over the couple of years I found the job not all that bad I always sent my heads out to the machine shop it was easier than trying to figure out the shim and bucket system and I know the valves would be done to. Along with the standard tools I recommend getting or borrowing torque wrenches, Harbor Freight puts them on sale from time to time I got the 1/4, 3/8 and 1/2 the crank shaft nut is usual higher than most 1/2 Torque Wrenchs. Another tool U will need is a Die for the exhaust nuts. It helps to clean them up before putting them back together also there is one exhaust stud on the passenger side that always gives me trouble I think the Die it's 6 mm x1.25. Expect to replace at least a couple of nuts and maybe a stud.