if you are interested in a 2FE as a "non carbureted" replacement, your money would be best spent on an injection system for a 2F platform.
what exactly happened to your F engine? do you have any interest in keeping a carbureted vehicle? if yes, simplest fix would be to source a donor F (or better yet a F.5) and have it rebuilt. despite some reads on this forum discussing parts availability, or lack thereof with the earlier F and F.5 engines, they are essentially unbalanced tractor engines that any reputable engine shop could easily navigate.
as far as an H42 5 speed, I've never heard of one. working on the presumption that you have a J30 currently, an H55 conversion would require bellhousing, flywheel, clutch, pilot bearing, slave, cross member, driveshafts(simplest of this list), split case, speedo cable, either and H55 e brake(would make for a tight fit and short rear driveshaft) or a single circuit rear axle(post '79 4X series or early 7Xseries), transmission hump modification, perhaps new pinion flanges not to mention any and all hardware.
none of this work is necessarily difficult, but it wouldn't be the fastest way to get you truck rolling again. although my only warning would be that with an H55/split case combo, your truck would be an entirely BETTER operating truck.
as a refresh, I would stay clear of a 2FE or 3FE avenue, just not worth it
HTH's Sean