That sounds a Great trip!
The North Corwall coast has its challenges for sure...its shallow and with prevailing winds can soon become a really messy and confusing passage!..no real "all states" Harbours and few bolt holes and fewer facilities.
As J says Padstow/Rock is the closest to full services again the Harbour is only accesable at nr High water..with fuel...although if you don't get in depending on Tides might entail a good walk..and a long wait.
Appledore would be worth considering for a stop over..a little off beam but Fuel available and trolleys to carry it...you can book moorings in advance,and plenty of B&Bs.
Lundy makes for a great stop over...but no fuel...unless you could work a deal with the Ferry man