All of the dining venues (with their corresponding operating times and if there's a charge) are listed in the RCI app - the current sailing info should be fairly accurate.
Not usually. You might luck into a shuttle, but don't count on it. The first should help with the test. BTW, most here refer to such sailings as S2S (side to side).
Welcome to CC.
Voom will work for that those things, though performance will degrade as you go north and may lose it altogether in some locations (due to the terrain).
RCI usually only do land tours in Alaska. Rhapsody is one of the oldest and smallest ships in the fleet. You can find ship related threads by picking her on the drop-down list on the main RCI page here at CC.
Yes. On board you will also likely have the option of waiting till the second day to buy - which could save enough to tilt in favor of buying on board.