Well it all depends on your budget and how anal you are. For me I wouldn't want to be back in there unless you recently had the head work done. Yes you can clean up the block and bottom of the head and install a new gasket as long as the head is straight.
I would point out its a good time to go ahead and have the head disassembled, cleaned, check if it needs MACHINED surfaced to make flat or not, no belt sanding!. Check valves and guides and replace as needed and do a valve job, replace the valve seals and all the gaskets. Usually this would run somewhere of 150.00 - 300.00 depending on what the head needs.
At the minimum if the head is flat then I would replace all the seals and gaskets on the head and cam towers, adjust the valves, make sure the block is clean and straight, replace the aux, crank seal, tensioner and timing belt. Change the oil and filter, new coolant and any radiator hoses that deem too old. Chase the Head bolt thread in the block, clean old head bolts if reusing and soak in oil and drain before assembly. I use copper coat on my head gaskets but that's just my opinion.
But then again once I pulled my head the block was next to get to rings, hone, rod bearings and bolts, oil pump, replace damaged pan, clean breather assembly and new hoses and gasket, new fuel pump, rear main seal. I mean after all just look how much easier it is to get to those top bell housing bolts.
And guess what while the engine was out it didn't make sense to leave the trans there all alone, pull trans and replace all seals and gaskets in it and give her new oil too.
You can see how this can get carried away quick. But that's how I usually do things and because of that the new owner, good friend of mine, has been driving it daily trouble free for past two years and no leaks