Rick You shoud buy a cheap suv and drive it down. At the boader dont tel them you are going to Belize just say you are going to Chetumal.
They are not taking any mordea at the boader now. Tell them all the stuff in the van is for your holliday and they may let you pass with no duties. If they want some dutie just list a smallamount but with 2 dogs you will not be bringing much unless you pull a trailer.
I had a van full and towing another van full and I paid dutie on 200. dollars.
You just have to bargan a bit.
If you have paid a little dutie the second check point is no problem.
My friend came down and he was pulling a trailer with 2 motorcykles and he passed with no problems.
I have been coming down for16 years and this was the easyest yet.
There are dealers at th Belize boader that will buy your van. If you need any help I am here in Chetumal.