Just back from a trip to San Ignacio and Caye Caulker. My wife and I stayed at the Cahal Pech Resort Hotel at the top of San Ignacio. I can't recommend them enough for their tours. Tikal and Caracol run just under $100US each with all taxes, fees etc... including meals. Each is a full day trip about 2 hours from town. We jumped in on a Tikal tour the first full day we were there, it was just our guide and one other couple for the trip. Caracol was just my wife, myself and our guide Bruce, who used to work at the Caracol site.
If you stay in San Ignacio be sure to check out the small ruins at Cahal Pech. Their stated hours are 8am to 5pm, but I was there at 6:20am and they were open.