A couple of things;
at 6'8" its going to be hard to find a
boat with that
headroom in your
budget, but they do exist.
Columbia 45 would fit. having said that I would not pick a big boat like that as your first boat.
At 30K ( USD I presume?) you will seeing a number of
boats in the 27-30 foot range, all of which will require substantial investment (?) in order to safely coastal
cruise. Anything larger will require more cash in order to sail.
On any boat small enough to have an
outboard engine you will have issues with space for
solar panels and
wind generator, especially for a fridge unit.
Back to the
budget thing; There are any number of small
boats that are good for coastal crusing,
Pearson Triton,
Pearson Vanguard, Flicka, She 29, Trintella 29,etc
etc. All of these are going to be old by now and will require lots of updating before going anywhere off a lake or a bay. None of them will be easy with your height.
Given all of that I would seriously take a look at the Westerly Centaur, 26 feet a good, well built cruising boat. Big for its size and you should be able to pick one up for around USD 2000-5000 in the
USA. I know of one going for about 2500 without an engine. Agsin it will require another 10k to make it
seaworthy.
Dont mean to put you off, but its a big undertaking, have fun and go!