Water Tank

I bought a 21 gal polyethelene tank with 3 threaded 3/8" connections and one 1 1/4" hose fill barb to attach a 1 1/4" hose. The tank has no fittings and I would like to mount the tank flat and be able to fill the tank as well as pull water out of the tank to a faucet several feet away, as well as drain the tank. I need suggestions for all parts. I am building a 5 x 8 teardrop and want to be able to have faucet in galley area and be able to pump the water out of the tank to the faucet.
Thanks,
Sherry

Thanks,
Sherry