Brak, I hold an 100 ton Master's of Oceans. I made my living for 10 years delivering boats up and the East Coast. $300 to $500 an day is not outrageous. I charged $450 the first day and $300 a day or any part of a day thereafter. Just so you know It cost me $50 to $75 a day just to pay pay for my liability insurance based on the value of the boat. I am sure you want Your Capt. insured. Crew was $75 a day and all three of us got $25 a day meal allowance. Travel expense were taken care of by the boat owner.
Considering the time involved and the financial returns I very rarely will do deliver"s now. Has to be the right boat and the right owner.
This sounds reasonable to me, particularly with the skipper being insured (which if your boat is smashed by some idiot on a jet ski, will expedite matters with the insurance people, as you took all due care, etc. by hiring a pro skipper in the first place!).
If it's too expensive for some, the alternative is to take a week off. If you can't do that, you probably earn more than a delivery skipper in the first place, so....