Western Belize and El Peten, Guatemala
The main attraction of the Peten region in Guatemala would be Tikal. Tikal is considered the New York City of the Maya world. It is perhaps the greatest of all Maya centers and one of the most visited. With the nearby sites of Uaxactun, Yaxha, and Seibal along with the island city of Flores on Lake Peten, this area should be high on your list of places to see.
There are several ways to Tikal, the easiest is to take a one or two day trip from Cancún or Belize City. There are daily flights with overnight options. The only drawback would be not having enough time to see some of the nearby sites. Another option is to visit Tikal during a general trip through Guatemala. There are daily flights from Guatemala city to Flores, actually the airport is in Santa Elena. Rental cars are available at the airport as well as taxis, vans, and public transportation.
But if you have between five and seven days to see the region, the best route would be through Belize. There are daily flights to Belize City from the States as well as other international departures. Several car rental agencies allow their cars to cross the border into Guatemala. There are also many private tour companies operating out of Belize City or you can take public transportation to Western Belize where you could transfer to public transportation across the border or you could take a private tour from Western Belize.
I recommend renting a car in Belize City, driving to San Ignacio (Cayo) in Western Belize on the day you arrive. The next morning you can spend the morning exploring the Cayo District as you head for the border. You will want to cross the border within 24 hours of arriving in Belize. There is a $10.00USD exiting tax as well as a $3.50USD environmental tax to depart Belize which is waived if you are in Belize less than 24 hours.
The border crossing can be quite intimidating due to the several steps required. First there is the departure process from the Belize side, then your car will need to be sprayed for about $4.00, then you proceed to get the rental car approved costing about $40.00, and then you will need a visa for about $3.00. The car will take less time than getting your visa but for a cash payment of about $10.00 to the people handling your car' paperwork you may also get your passport stamped in a matter of minutes. Lastly, there is a small wooden bridge with an gate at the far end. You, as a tourist, will be charged a toll to cross the bridge. The official toll is $4.00QZ but be prepared to pay $20.00QZ, about $3.50USD. The good news is upon returning to Belize you only need to pay for a car spray at the Border.
The first fifteen miles of road in Guatemala is unpaved. A few miles after the paved road starts the Maya Site of Yaxha lies a few miles to the right. The road in offers a spectacular view of the Lakes. It is free to enter the site and takes about two hours to completely enjoy the site. You can catch a late lunch at el Sombrero on Lake Yaxha.
From Yaxha it's only a little over an hour's drive to Tikal or Flores. You can stay at one of the several hotels within the Tikal National Park or for about $30.00USD per night you can stay in nearby el Remate on Lake Peten. It takes two full days to see Tikal and another day to see Uaxactun. You'll need a permit from the office in Tikal to drive to Uaxactun and the road is rough (four-wheel drive required). It will require another day to drive to Seibal (Ceibal) and a half day to drive around Lake Peten and visit Flores.
The drive back to Western Belize and the border crossing takes about two hours and should be uneventful. Once you cross the border the site of Xunantunich is worth the few hours it takes to see the site. You will need to take your car on a small free ferry at San Jose' Succotz a few miles from the border on the left side of the highway. A tip to the ferry goes without saying. From there you can see many sites in Western Belize, drive to the Southern Belize coast, or take a fifteen minute flight from Belize City and lay back on Ambergris Caye or Caulker Caye.
Midas Resort Single cabins about $35.00/night. On the edge of town with an easy walk to restaurants and shops in San Ignacio. Great value, book ahead because it is usually full by nightfall.
Cahal Pech Cottages Twin and double cottages about $50.00/night. At the small Maya Ruins of Cahal Pech.
La Casa de Don David Charming small hotel on Lake Peten. Rooms for $22.00/night or $30.00/night with hot water. David Kuhn, the original "Gringo Perdido", is a great source for information on the area. There is a restaurant which serves an American version of local cuisine and also has a good selection of Guatemala's best beers.
The Jungle Lodge Right inside the park. Rooms about $85.00/night. The reservation page on this site did not work but you can e-mail them to make reservations.
There are two other hotels in Tikal park. You can e-mail for info at firstname.lastname@example.org
Crystal-Belize At the Belize airport. They will provide all the paperwork to take a car into Guatemala. A real time and hassle saver. You will need four-wheel drive if you plan to see Seibal, Yaxha, or Uaxactun.
Linea Dorada Bus service serving the Guatemala-Belize border to Flores and all around Guatemala.
Belize Bus Schedules Several Bus services within Belize serving the border.
Tropical Air Largest airline within in Belize.
Maya Island AirFlights within Belize and Flores, Guatemala.
Belize Net Outstanding site with everything you will need to travel in Belize - hotels, weather, maps, and attractions.