Hotel in Venice near train (arrival) and Piazzelle Roma for bus departing to airport

A two word question is tough to get my teeth into, but here goes.

I wouldn't, and that is where it goes from.

There's no real reason to stay right near the train and/or bus station. If you arrive by train and walk even 5 minutes, you'll be in the heart of the less touristy Venice with tons of lodging options. Go to Tripadvisor, put in your travel dates, sort by ranking and see what kind of options pop up within your budget.

It's hard to recommend any lodging at all without more information about your group size, budget, travel style etc.

I always stay in an apartment in Venice so I can't comment on hotels.

Where you stay depends partly on what time you need to depart.