I was thinking about this but I'm worried about reaching the top trans bolts with the long block assembled. Maybe it wouldn't be too bad.
I'm curious, you mentioned going back in with the long block but I was just curious why you suggest this? Is there a significant advantage of going back in with the long block all at once?
It's far easier to successfully reassemble the head, cams, timing chain, gears etc out of the vehicle than in it. Yes you can do it in the vehicle, but it's worth pulling the engine just for ease of access.
The head is heavy, and lifting it into position in the vehicle is a risky endeavor. High chance of screwing up the new gasket.
I've done both, and preference would be to pull the engine for sure.
To remove the engine, put a jack under the t-case cross member, remove crossmember bolts, lower jack until the engine is about to touch the firewall. This gives you better access to bellhousing bolts. You'll still need a couple of long extension bars and a swivel socket or swivel joint to access the bolts with the ratchet wrench down by the t-case.
Once to bolts are out, jack crossmember back up and put a couple of bolts back in.
To remove the engine, you need to support the weight of the transmission. You can use a jack for this, or if you need to be able to move the vehicle, loop a ratchet strap in a big long figure 8 loop over/around the frame rail, under the front of the transmission, back over/ around the other side frame rail. Tighten ratchet strap enough to support the weight of the transmission.
Remove the radiator. Remove the engine fan so you have enough room to get the engine in and out of place without damaging the radiator.
Here's my engine on the crane ready to go back in
And back in
I've done this solo several times now