[NextNewell]

In the original picture of the box there are two fuse holders. Are both of them wired into the contactors? If so, I would guess they are each wired to a separate contactor coil. If so, I suggest turning odd all power and then measure the ohms resistance through each of the circuits to neutral or ground. They should be the same. The fuse blows due to too much current. Current will be too high if either the input voltage is too high or if the resistance in the coil is too low.

If the  oil ohms are ideal tial then I would pull the power leads to the fuses loose and measure the input voltage. If those are also identical I'm gobsmacked stumped to explain the fuse blowing.

Since I removed/checked/reinstalled the contactors, the fuse hasn't blow  - yet. But,  now when I turn the switch to shore power, I don't hear the contactor engage and there's no power coming into the coach. 
I've always been the DYI guy, but that almost guarantees me spending more time, money, and effort attempting to learn/figure out what, why, and/or how. So because I lack the proper knowledge/equipment, I'm not able to measure ohmn's, or current, and my common sense tells me to get an electrician back asap.