CaliBlueFrog - I'm only a one time visitor but I'll give you my two cents worth - When I was planning fishing, I got a little concerned about posts about guides not showing up - we weren't staying in town so walking around looking for someone wasn't an option - so I booked thru fishingsanpedro.com (same guy as Coconets) on Capt Jeff's recommendation and it worked out great. I'm sure you could probably go direct to a captain and it would probably be less expensive, but it was so easy going the route we went. Ask for Poncho if you can get him - he's about 65, entertaining and has a great honey hole for snapper. While he's cooking a beach bbq with your catch, you swim and relax on a quiet, calm beach. That made a nice half day for us. As far as all the rest, I missed the ruins tour but my friends loved Lamanai with a guy named Carlos (can reach him through Mary at M&M Rentals), he's a cutie and very reliable. They were impressed with the river boat as they saw other tours on some uncomfortable looking boats. I should stop with touring since I didn't do any.
I will say we snorkeled with Carlos too and I thought he was very knowledgable. We were only out about 2 hours which, considering the strength of the water flow by the reef, was all this one was up to. It was my first snorkel so I was in awe. We asked him to plan to take us in more of an off time so there wouldn't be so many people in the water and that seemed to work out nicely.
Other than that, leave some space in your bag or give some stuff to your guides as we did and go shopping. I love the textiles I bought from the Grandmother, daughter and granddaughter team outside Fido's. I had to buy something from them everytime I passed! I actually picked up some cute jewelry from some school kids and there are shops with nice clothing, jewelry and art. Have fun! I am having major withdrawals.