A few thoughts as to "rewatering".
We carry 3 collapsable 50' hoses in addition to the regular hookup hose and a "water thief" used to hook up to spigots where the faucet threads are stripped. In many campgrounds this will get us to a spigot.
We often bring 2 eight gallon water jugs in the back of the truck and have worked out a fairly easy way of adding that water to the tank. DW holds an automatic transmission funnel - this is a plastic contraption with a flexible spout and pretty good capacity. I carry a two step stepstool in the TM and with my foot on the upper step can rest the jug on my thigh so my arms don't have to bear the entire weight of the jug while pouring. This works pretty well even for two middle aged deskpushers.
With reference to the bilge pump option, a similar (perhaps identical) kayak bilge pump is available at West Marine (
www.westmarine.com) as part # 839625 for $19.99. You may find that West Marine has a closer store than REI. West also carries several electric pumps including the Water-Buster Battery Powered Pump (part #447235), a 3 D cell self contained unit with 200 gph capacity, for $36.99 which could be used to pump from a bucket into the TM fill port. To flip a switch would sure be easier than standing there pumping! - camp2canoe