welcome to the board and welcome to cruising. You will love the Sun, she is a really wonderful ship.
Laundry: you are right, no self service but normally about 1/2 through the cruise you will be offered a change to fill a bag with clothes and they will laundry it for $20. The bag may not look very big, but it is amazing how much you can stuff into it.
Tipping, you will be assessed $10 per adult and $5 for kids from 3-11 each day. They consider 12 year olds adults. Other than that and the auto tip of 15% on all drinks you really don't have to worry much about tipping anyone else except for the kids camp councilors. We do tip our cabin steward a little extra and we tip extra in the upscale sur charge restaurants like Le Bistro. This is not something you have to feel obligated to do.
As for shore excursions, you may find out it is much less expensive to book them privately. I would suggest you go to the roll call both here and on CruiseCritic to see what others sailing with you are planning. Often a group will get together and do tours. It is fun and less expensive.
Hope this helps you some,