The cache is solved by taking the answers to the questions from the caches Underwater Bridge GC46RJG and Three Bridges GC3XXBH [I suggest you do Underwater Bridge first].
You should have found 2 years. Add these 2 dates together to get a 4-digit number.
Add each of these individual digits together, to get a 2-digit number.
This is what you need to put into the following co-ordinates:
N 52 XX.012 W 001 34.601