lots of sellers say lots of things. and yes, that's a big project if it's your primary driver. there are significant rewards once it's finished , but that could take quite some time, especially if things go wrong along the way.
the cheapest would be fixing the carb you've got. might just need a new choke or even just a cleaning. an engine swap will always be a big deal because of the "devil you know" vs "devil you don't know" conundrum. unless you bought a running Camaro/Firebird/S-10 so you knew ahead of time that the parts are good-to-go. that would give you a bug leg up vs a junkyard swap.
you can just tip your head under the front of the bed. the stock mounts look like this. note that it looks like something should bolt to it? yours will have something there. specifically the second half that the rollbar then bolts to.
with factory tow package you get 5k. without it you get like 2k.
plus each state has rules about the towed vehicle having it's own braking system for emergency separation (usually anything over 3k, but it varies).