Tikal is a dont miss - if you dont want to arrange an independent trip (which is a lot of work if you're not staying overnight at one of the hotels near the ruins) take a tour. IMO the issues with Tikal are not specific to single women; if there is unrest in the area being a man wont help. The unrest in the Peten is supposedly no where near Tikal but a local person can give you up to the minute info.
I went alone the first time - stayed 2 nights at the Jungle Lodge and was fine. At the time, aid workers in vans were being pulled over and robbed and I was a little nervous between the airport and the entrance to the park, but once inside Tikal, there was a lot of security. Went back a 2nd time on a day trip from Mopan River Resort.
Caracol is also cool, but supposedly there are more issues there than by Tikal currently. Then again, my info is from June, when I was down in Belize. Situation could have improved.
Chechem Ha is another dont miss spot.
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