Ahh, the fine memories this thread brings back.
I solo drove my `86 FJ60 out to Colorado a few years ago (23 hours each way) and collected a nice 5x6 free-range organic specimen. I took the elk to a butcher in town that would flash freeze it. The entire butchered and frozen elk fit into a single 120qt Igloo cooler, but just barely.
I strapped the head and antlers onto the roof rack (along with spare tire, a highlift, a shovel, and a couple of 5gal gas cans) and stuffed the salted hide into an XL game bag. On the way home I dropped the head, antlers, (for a European mount) and hide at a local taxidermist. I now have grizzly, moose, caribou, and elk 'blankets' from the hides I've collected and had tanned (hair on).
I slept in the back of the FJ60 with my gear and the cooler on the way out and on the way back.
My biggest problem was getting over the I-70 pass to go through the Eisenhower tunnel - that FJ60's 2F engine had 135HP when new and I did that trip with 200K on the odometer. If I recall, l had to drop into 2nd gear to climb that pass - semis would even overtake me, but we made it just fine.
That FJ60 had less interior room than my 5th gen 4R, but a roof rack, trailer hitch mount basket, small utility trailer, or what ever extra storage capacity you can get would definitely be a good idea.