Interesting looking boat Nige, should be fun.
If you're not doing quick refills, you could always use a 'squeezy' bottle (washing up liquid bottle) with a bit of silicone tube and metal tube to connect to the tank filler and 'pump' the fuel in with that.
A Power panel will not be much use unless you also want to lug a 12V battery as well (you don't need the pump or starter connections so its a bit overkill for just a 2V supply).
With it being a small pull start engine, you may prefer to use a model car type "all in one" glow plug driver. Get one with a high capacity battery, as using a pull start might involve it being connected longer ....
Cheers
Danny
PS. Don't forget to add some bouyancy inside your lid, then if it comes off it won't sink.