I would say that any 5" or 7" screen fishfinder / GPS combo with a Navionics chip will suit your needs just fine. Humminbird Helix 5 or 7 or Lowrance Hook 5 or 7 with the chip will definitely work.
West Marine is having a sale:
https://www.westmarine.com/buy/hummi...58?recordNum=4
For navigation purposes only a 5" screen is sufficient. If you want to split the screen and run the fishfinder at the same time I wouldn't recommend less than a 7" screen.
That would work nicely for you. A lot less dough than the Simrad unit.
Of course if money is no object...Go nuts and buy the latest and greatest!