Have just spur of the moment booked for me and 18yo dd to go for 10 days in July. Am fed up of being scared of never travelling as on my own with dd.
Staying at the Xcaret Occidental which is AI and looks lovely after seeing it mentioned on another thread.
Any recommendations about excursions, etc. Pre book them or wait till I get there. Am planning on getting the discounted pass to the Xcaret eco park next to the hotel, so think I can get passes fairly cheaply for the duration of the stay.
I read it's best to pay for stuff in pesos locally rather than dollars as better exchange, is that right? I guess I won't need much money as it's AI.
But it would be nice to go and have a look round Playa del Carmen one day. Especially as I've read there's a Bath and Bodywork shop there which I'm insanely excited about. In fact dd reckons it's the only reason I've booked Mexico! 
Are there ATMs there if I need to take money out? This is why I never go on holiday because I worry too much and all the little details seem overwhelming.