There are no reman'd 192C's that I am aware of. We do have some reman'd 182C's. Does your boat have a hard top? If only a canvas top or no top at all you will be OK with an internal antenna. The Garmin 192C w/internal antenna and a second mounting station would be ideal. This unit has built in cartography so you will never need to buy a chip for charts. Just turn it on and go wherever you are.
You mentioned the 182C and 188C. The 188C is also a Fishfinder and only comes with an external antenna. I don't think that is what you want. The 182C will cost just about as much as the 192C once you add a chart chip. Plus the 182C is dicontinued, but there are still a few available.
If the 192C is within your budge go for it.
Garmin 192C
2nd Mounting Kit