If the garden hose is too big they make a smaller plastic "Nozzle" that is about a foot or so long for flushing out the tank, has an angled tip. Any RV place should have.
As to which type of anode you need. Check with surburan. make sure you have the MODEL number of your heater handy.. I'm unable to advise.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times