How fast do you want to do it and is
fuel costs an issue?
Assuming 20kt
cruise speed and 10hr days along with 6 days per week....a week or two if everything goes perfect (no break downs, no significant
weather issues, etc...). This would be a
delivery run and not fun.
A more realistic option would be figure an average of say 100-150miles per day and 4 days travel per week...so maybe a month. That's still a bit agressive for our taste but you are a lot less likely to try and go on a day with bad
weather.
There is plenty to see so it's very reasonable to take 2-3 months and enjoy a more relaxing trip.
If it's a month down and a month back and you flush the
engine when hauled out, shouldn't be a big deal to have a
raw water cooled
engine.