600 feet?!!! Bloody Hell! If that's how close he keeps his friends...
Sometimes friends kept at a distance remain friends longer than the ones up close. And it's also possible that 600 feet is as close as some of Bobert's friends want to be *** ***. But we might suspect that the location is in anticipation of his own "quest for solitude" after the guests leave(??) If you're gonna be in the doghouse, you need a nice doghouse - as far out of sight as possible.
If you're using a pump, the few feet of elevation isn't really very helpful, and the 100 feet of hose probably "erases" any good that is obtained from the elevation.
You have a tank on a trailer to get the water to the vicinity of the Spartan. It might simplify your plumbing if you used the mobile water tank just to refill a fixed tank closer to where the water is used, or just parked the trailer closer to the Spartan where you could use a ten foot hose instead of the 100 foot one.
If the trailer is really suitable for carrying 425 gallons of much of anything, the tank on the trailer would be enough elevation to feed the pump through a short hose.. Even the "half full" ~200 gallons is close to 3/4 ton of water, so we'd suppose that even by West 'Ginny ratings it's probably on a trailer with at least ten inch wheels(?).
RECOMMENDATION: Since gravity feed alone didn't work, the water should be moved as close as possible to the pump, and the shortest convenient hose should be used to connect the water tank to the pump.
Bobert will have to work out details with local consulting staff about how much weight to give to "ugly factors," interference with traffic patterns (foot, livestock, and farm implements), and whether drainage1 at the connection is adequate for any spillage/seepage that's inevitable with "mobile" liquid transfers.
1 There's "drainage" and then there's "holdage." If the latter is more appropriate, just call it the new birdbath, even if it's just the chickens that use it.
Finding "short hoses" can be something of a problem.
Garden shops seldom have anything less than 40 or 50 feet (in quality that will stand even low pressures for sustained periods).
RV shops may have "potable water hoses" in lengths down to about 7 feet (and up to about 30'), but they're stiff and a nuisance to handle, and are seriously overpriced.
"Washing machine hoses" are rated for constant pressure, but again are not flexible, and are "female on both ends" so an adapter is required. They also are usually half-inch diameter. That might be big enough, but IMO even 5/8" or 3/4" would be more suitable.
My Home Despot has recently had "hose reel inlet hose replacements" in about 3 or 4 foot lengths, but I'm not sure the quality is any better than what usually comes with a hose reel, which is sh*tty at best.
A length of hose suitable both for filling the tank and dispensing the water might be a consideration if the water is left on the trailer for use.