For use as an RV this amount of cooling (7tons) and distribution is a bit overkill. Being that 3-5 tons is usually used on large RVs / tour busses like presvost etc..
The water loop on plate side is parallel from both plates straight to 30gal tank. This setup mocks that of large format industrial chillers. Each compressor is independent to a plate exchanger. TXV expansion valve, evap coal, and plate exchanger as condenser.
The water tank itself has a set temp of what you want your coil temps to be on the air handlers. So basically the two compressors have 4 stages to maintain the temp.
1st stage 70% one comp
2nd stage 100% one comp
3rd stage one comp at 100% and other at 70%
4th stage both at 100%
These are controlled by a temp control for each stage as to not overshoot the desired water temp. Say about 1.5 to 2deg off per stage.
The tank is insulated like mad and can store the chilled water. This means (in Vegas) I can run compressors at night when it's cooler and easier to chill and it will help get through higher load during peak day.
If you had room temp water and turned system on all for stages would fire up and chill the 30gal as quick as possible. As the desired temp is reached and to just maintain the water - it will cycle down to just one or two stages.
Idea is based to be more efficient than just running 5 rooftop units.
Difficulty like you said is condensation. All water lines need to be insulated and the air/water handlers need condensate drains to outside bus.
Cool thing is the main roof unit already has this setup. I'm just gonna run high pressure chilled water through the rather large original (but modified) condenser coil that has the blowers. I put speed controllers on the blower mothers to run them all at lower speed and have less ducting now so it is fairly quiet (this main unit is in my kitchen though, so it's not a big deal for some amount of noise)
The front lounge is tricky as the air/water coil I will use here is the old heater coil from roof. (6' long but only 1.5 deep and 5" wide) so I can build a flat but long handler that hangs sorta where old parcel racks were above the side windows.
Each compressor is 3.5 tons. Original roof coils were 8tons combined so Split it's basically 2 4 ton evap coils.
Each plate exchanger is rated around 3 tons or more pending water and refrigerant flow rates in told from manufacturer.
Here is the chiller control box I'm building