Obviously a great deal will depend on your cruise line/ship. Without specific, I can only be general. If you are worried (as in diabetic and needing specific meals at specific times) contact the cruise line directly.

Let's break your question down:

1. Checkin. Most checkins have standard lines for normal travelers. Some will further break this down into Decks 3-6 and 7-9 (for example). Watch the signs. Time will vary. You are showing your paperwork, passport and Credit Card for on-board charges. Avoid getting behind 'groups' as they normally confuse the staff on who belongs with whom on the charges.

THEN many cruise lines will have 'special' lines for their repeat passengers (cruise club ABC or what ever the line calls it). If you fall into this group, it is normally a much shorter line.

THEN if you are in a Suite many lines will have a further special checkin for you. Obviously this would be the shorter line, but only if you are in a suite!

Watch the signs for your applicable condition.

2. Embarkation. This will vary somewhat by cruise line. Some lines (after the security checkin and the wonderful 'welcome on board photo op') will greet you at the gangway with Champagne and assign a staff member to walk you to your cabin. Other lines will say 'Hello' and point you in the right direction to find your way yourself. Upscale lines will be more personal.

Be aware that on the 'find your own way' and even with the personal guide, you may be asked to walk up or down a few decks instead of taking the lift/elevator. The elevators on many ships are controlled for the use of baggage delivery. OR there may be the central elevators used for passengers and not the rest. Your guide will KNOW what is happening.. tho may take you the 'walking route'. On your own, you may need to ask (or they may station people at the lifts saying 'no' or 'use the forward/aft lifts only').

3. Dining. Most ships on turn-a-rounds WILL have some level of dining available. A lot will depend on the ship and the destinations. For example, Princess in San Juan had open seating with limited menu in the main dining room from noon to 2:30pm. It was quite simple food (no courses) but very nice. (this was not a turn-a-round as it was a continuation cruise for 20% of the passengers so they really had a port day) Then most ships have the buffet dining room open MOST all afternoon. There may be a lunch then a snack version .. then more of a 'tea' towards sailing time. The pizza and burger and other small venues will most likely NOT be open in port.

Ask your steward when you board, or read the newspaper in your cabin. It will tell you whats open when. Normally in a US port, all bars are closed however. THEN shortly before sailing there will be the Emergency Drill ... at which point all food service ceases and probably closes down.

BUT not to worry if you are on the preferred Second Seating .. once the ship sails the buffet normally opens up.. or they serve tea .. or some ships have a sushi bar that opens at 5pm (appetizer for the 6pm crowd and tide-over for the 8:30pm crowd).

Normally room/suite service is NOT open until after departure. Some lines will provide Suite guests with hors dourves at sailing.

Hope this helps... each line is a bit different. Was on one line (nameless) who served NOTHING until your dinner time but that was several years ago.