Lance, I think this is your 'list'...
...altho' unique personal circumstances will shape the details:1. Sales or use tax on the purchase price of the boat (new or used) is determined by where the sale is executed (not necessarily where the boat is being shown and for sale); speak with the broker (if one is involved in the sale) and the tax authority (usually, a county tax collector vs. city or state authority) where you hope to conclude the sale.2. States will usually (not always) allow you a 'grace period' in which to commission the boat and leave state waters, which eliminates tax liability in that state even if tax is usually assessed; again, check with local tax authority and broker (the latter will know all these ins & outs, as you would suspect)3. Insurance is at your option unless a lender forces requirements on you; doesn't sound like that applies to you.4. Passage thru subsequent states without liability for Use Tax is allowed but within restrictions established by each state; if you are e.g. headed south towards the islands before sailing back to the UK, you will usually find local authorities accepting of your presence for limited periods of time should you be passing south thru the Intracoastal Waterway.5. Your bill of sale will be your only legal document during this time, unless you choose to register the boat in a U.S. state or are eligible to federally document it (don't know if you carry multiple passports or not).6. On arrival back in the UK you will owe VAT of 17.5% on the assessed value (not necessarily what you paid for the boat); if ownership was held by a non-EU citizen, you could request Temporary Importation (good for 18 mos. of VAT-free status) or full Transfer of Residence relief using a C104A from HM Customs. In the latter case, you'd end up with the equivalent of a VAT-paid boat without paying any tax, and that status would transfer to any subsequent (EU citizen) owner.Europeans - and especially Brits - find boat purchases in the U.S. to be a bargain when compared to options back home, and seek to 'rent' their purchase for some time, enjoy cruising, return home and resell the boat in a VAT-free zone for perhaps a small profit. As the EU expands, VAT-free zones shrink (e.g. Malta and the non-EU portion of Cyprus both formally join the EU May 1st) and this becomes a bit tougher to do - altho' there's always Gib, the Channel Is. and comfortably-slack Spain.Jack