Well it is probably a number of things depending on how long it has been sitting. The cables are probably dried up and the carbs are stuck. Most likely anyways.
Remove the cables from the carbs and then from the throttle housing. See if you can move them, if not, then you can try to lube them. You can get a cable lube clamp that goes over 1 end and has a hole for a straw to spray lube. Spray iot a couple times and let it sit and see if it moves. You may have to repeat. If it does not move, you can get new cables from honda and from motion pro. Honda cables are fairly pricy about 2x the price of motion pro which is about 12 each.
if the cables move ok(they should move with very little force), then tackle the carbs. The slides are probably stuck.
The ride IS the adventure. The destination is just to get gas!