My experience with mobile homes is extensive but from long ago. Back then, the supply piping was all the same size in the entire unit. On that basis, and if that is the case with your unit, your idea should work rather well. But the present supply near the water heater helps keep the pressure even between the hot and cold supplies. Moving the input point farther from the heater probably will make the hot water pressure lower than that of the cold due to pressure losses in the longer piping run. Will your idea work? Yes, but perhaps not as well as the system does at this time.

Okay! Thanks! The reason I want to move the inlet is because I want to install a whole house filter. But I will need to move the pipe so that it will be in a place I can stand up and have easy access to change the filters....... this would mean running the pipe from the main to 15' away and then through the filter and then back 15' to the original mobile home inlet.

Question... if I just run the pipe from the main another 15' and tap into the cold water pipe under my kitchen sink (which is on an outside wall) would my hot water heater still get water and would the pressure be compromised too bad?

The extra piping plus the filter will result in some pressure drop. Unavoidable. But the pressure may be adequate after the change- or it may not be. No way to tell from here. If you would call it "great" at this time, it probably will be OK later.

So I can just plumb the main straight into my kitchen sink cold water inlet and it will still flow to my water heater and everywhere else after I cap off the current inlet?

Water will flow in a pipe in whatever direction some force pushes it. Only an on-site evaluation by a experienced person can predict the effect on pressure.

Thank you Bus Driver!!