I would recommend that after you have all the woodwork done, you toss the roll of chicken wire you would be using on top, and run a few laps around the yard with the unfinished ark to see how it actually handles in the rough. Doing a weight test before you attach the wire makes lightening the frame (etc.) a lot easier if it turns out to be necessary.
Ditto for modifying the wheel system, if you need to.
If the unit is too heavy to move EASILY you'll find yourself moving it less & less often, possibly even delaying until the chickens have a bare dirt run--which is something you shouldn't do.
The whole idea behind having an ark is to give the chickens fresh graze every day or two. If they wind up eating everything green in their run, they are having to eat stuff they would normally bypass. Less nutritious plant parts, etc.
Basically, the chickens should never eat more than about 25% of the greenery in their run before you move them to fresh pastures.
So you will definitely want to be able to trundle your ark around like a shopping cart.
Re that: You should not have to do anything at all to ready your ark for a move. Just grab it & go. That means no feeders or waterers sitting on the ground, and a floating chicken ladder that won't stub into the ground as you move the ark.