We'd like to check out Placencia while we're at San Pedro this trip. Is it possible to fly over to Belize Muni, get a car and drive there and back in a day ? Or is it too long of a drvie and would it be better to fly directly to Placencia ?

fly - even that will be pushing it to check out Placencia properly and get back in a day

I think you'll have to fly to the Municipal airport and change planes to get to Placencia. At least you have to change planes coming from Placencia to San Pedro. Our original plans were to take a bus from Placencia to BC then fly to San Pedro, but it would have taken all day. Granted it would be faster by private car, but would still eat up a big hunk of time.

A drive to Placencia and back in one day would really be pushing it if you plan on doing anything while you're there. However the drive over the Hummingbird Highway is beautiful. Find an extra day and spend the night.