Its amazing how many points of analysis can be brought to a couple little bottles of suntan lotion.
Do we really know what size bottles of stuff she usually carried? Besides the tidbit that cumulatively her shell-care products weighed many pounds?
I travel long distances a lot by car, sometimes for 2 week stretches. A small car fills up easily and quickly. Personally I use little travel bottles for shampoo and conditioner and lotion; toothpaste is the only regular size item I carry.
Her trunk was full of gas cans and water bottles, she was carrying camera equipment, a DVD player, and a computer, plus personal luggage, plus a gun and knives and whatever else. If she planned ahead on exiting TA's house quickly after killing him, maybe she didn't want to be carrying a lot of stuff and opted for small bottles.
Who knows. I don't think the size of her bottles or the fact she bought sun block equals she thought she was going to Cancun. She was hacking into his accounts. She knew there was not a ticket in her name, there was one for Mimi, and there was no way Mimi's ticket could be transferred to her even if Travis magically changed his mind.
Nope. Not Cancun.