It sounds like you have everything worked out the way that you and your wife want to do it, and that is what matters . Wishing you a safe and happy trip and a great vacation ! !
Wait a minute... Just between one breakfast and one dinner the two of you are gonna drop over $200?!?!?!?!?! On buffets??????? Can you not see some possible reason your SIL is renting a timeshare besides "trying to control you"?