Laptop as monitor for Montana 600

is there a way to use a laptop as a much larger screen for my Montana 600? I am using map software (chip) for hunting (onyx hunt maps) that require a garmin device and it runs fine on the 600, it's just too small to make good choices quickly.
I've tried searching and all I can find is how to use the NMEA data from the gps to the laptop...or downloading data from the gps to a laptop after a trip....nothing about a way to get a larger screen.
I can make my laptop into a gps.....but I cannot use the hunting maps without certain Garmin devices......that's the conundrum.
Any ideas?
It seems so logical, there must be some catch I'm not thinking of

 

Nuvi, thank you re the reply, I've used my iPad with a Bluetooth gps node and that is about the smallest screen for In vehicle use that is practical. However there isn't enough memory in my iPad to store more than a few dozen sections, when we are scouting an area we drive many miles of roads, knowing legal hunting ground is important but we had many instances where I hadn't downloaded enough of the area because I ran out of memory or time (it takes literally hours on a hotel wireless speed to download) and yes, I planned to mount the laptop in the vehicle.
I guess I'll keep looking.