Given those intended use outlines, you are not going to need a lot of mods. A soft lift with thin leafs will net you the best ride (short of coil type suspensions), 33" tires, 4:11 or even 3:73 gearing out of an FJ60 will get you to the highway speed you want without killing the 2F, upgrade to four wheel disc brakes, power steering, AC, nice cumfortanle seats, etc.
Rebuilding the 2F is going to be costly but it will last fou years and will get you down the road just fine. Affordable Fuel Injection might be worth considering but hardly a "must have" given your intended use. The stock 4speed is a fine transmission and you have no need for lower gearing. 80 axles would be nice for the wider track and bigger birfs but, again, will not be of any use on the highway. You can accomplish the width with rim back spacing or wheel spacers. A V8 would be "fun" but, again, you are not trying to pull giant tires, climb giant hills, or blast through giant mud pits. A coil suspension from something like an 80 would be nice but expensive to have built for you and hardly necessary for an occasional use highway/farm car.
Keep it simple and rock on.