If you wind up with an '817, and, IMHO that'd be a great choice, I highly recommend the
"big battery" and "One Fast Chager" from W4RT. Lost more capacity in the battery, & it charges much faster than Yaesu's obsolete dumb charger that's built into the radio. There's an issue with W4RT's packaging of the combo, but it's easy to fix & electrically that combo is super!
For an antenna, you could consider a ham stick or 2 or 3, mounted with something like this...
I've never tried that, but that looks like a very convenient antenna setup. On a car hamsticks get out
very well, and I'd think that mounted with one of those vice-grip thingies and worked against either a couterpoise or a ground, you'd have decent results. For example, I worked the Netherlands mobile with an '817 & a hamstick on the car with good, Q5 copy.
You can probably buy hamsticks for the bands you want to cover for less than the cost of a Buddipole. Just sayin...
Oh, and if you're planning on CW...don't forget a CW filter for the '817.
Whatever you get, it's very probable that it's going to be lots and lots of FUN!!! Enjoy!