At your power level, I think a 4L80E is way overkill. Heavy, requires an expensive controller, and possible tunnel mods -- for what gain?
I installed a B&M 700r4 in my car a couple years back to replace my TH350 and am very happy with it so far -- I'll be even happier after I get a working lock-up converter in it. I bought the trans used from a good friend who bought it brand-new at Summit.
The TV cable really isn't a big deal. The throttle linkage on your GoEFI looks exactly like a Holley. I'd try these:
Holley Transmission Kickdown Brackets 20-121 - Free Shipping on Orders Over $99 at Summit Racing
(bolts on throttle linkage to provide a connection point for the TV cable)
Holley Throttle Cable Brackets 20-95 - Free Shipping on Orders Over $99 at Summit Racing
-- this *might* work, although it looks like your GoEFI doesn't have the notch in front of the driver's rear mounting hole to correctly locate the bracket. It's hard to tell from your pic. Look at a Holley base plate, you'll see what I mean. Worst case, you could get the Bow-Tie Overdrives Easy-TV. It seems to be well regarded, if maybe a bit pricey. (IMO)
It cost me ~$200 to have a driveshaft shortened+balanced at a local driveline shop, and that came with new u-joints installed.
As for the gear-spread difference between a 200 and 700-- I only have 3.55s in the rear and in most light throttle street driving, I'm in first gear for a couple seconds, at most. My 10" converter also negates the wide split a while street driving, and I can't hook up in 1st gear WOT on the street. At the strip, the closer-ratio 200 might be nicer. I would guess the .7 vs .67 OD difference isn't enough to notice. But having OD has made the car *much* nicer to drive.
I had a to drill a couple holes in the frame after I slid the trans cross-member back. Very easy. Speedo cable screwed right in. My TH350 trans cooler lines were a direct swap. My stock column shift linkage worked fine too. It was a little tight when pulling it all the way down into "1", but it worked. I've since installed a B&M Quicksilver and like it much better than the column shift.