Jim
If you are in Canadian water, you generally are in Canada. This is definitely true if you anchor. All the regulations on hand guns apply - It is a criminal offense not just a citation. Same goes for some porno - particularly kiddie porn or violent porn - criminal not just naughty.
The height issue - the mattress size can be changed or extended easily but you will not find a lot of sedan height selection that makes you happy. It is hard to raise the top on most models but sometimes you could lower the centre aisle at from the floor. You lose some space in the engine room or cockpit but maybe still a decent trade.
The wine issue. Try making some on board. In 15 days with a little skill grape juice concentrate equals wine. I do and it works well. It is also 90% cheaper than the expensive alcohol prices in Canada.
I think a 35 footer is too small for continuous travel. Try something bigger and the possibility of more headroom could more likely be there.
$300,000 seems way too high for a boat unless you are incredibly fussy. Try around a $100,000 for a decent used vessel and although some people are much lower and some much higher, count on maybe $3000 a month to run I am lower on both the capital and operational cost and I would say we live pretty well.
Try four months solid off in the summer with no return to home before committing to full time or winter. I do this and find it quite acceptable.
Lastly - the mail- I have someone come by once a week and gather it up and turf it into a big cardboard box reading none of it. I know which recurring bills to pay so I stop at a branch of my bank once a month and pay roughly what I think as I can always phone for an accurate amount. My only beef is Hydro estimated readings which always rip me off. Next year I am going to phone in some fake readings . If they can cheat, so can I .
