I have a GlobalSat Bluetooth GPS receiver, model BT-338

Here's how I got it working on the PE:
Used Z4ROOT to Root the eDGe (allows "Mock locations")
Go to Setting - Applications - Development
Check the box for "Allow mock locations"
[back] button twice
Network controls
make sure GPS unit is turned on, and positioned where it can find satellites
make sure Bluetooth is checked
Bluetooth settings
Scan for devices
pair with your Bluetooth GPS
Install BlueGPS
check Start/Stop GPS (to checked)

Run Google Maps (I used my emulator to find on Market, load, backup and copy)
Allow location / verify the location it indicates.
zoom to street name level
Begin sliding window around to cache nearby maps

Things I got stuck on include:
You have to have the PE "rooted" to enable allowing mock locations.
You have to have that checked before installing BlueGPS

But the good news is that turning the GPS "on" in BlueGPS seems to have solved the "paired not connected" problem in Bluetooth Settings.

I tried cross-loading MapDroyd to cache map data, but it wouldn't install on the PE, even with the GPS connected and working. I've been told Google Maps caches to the level you zoom in and to the limits of available memory. Otherwise, you need WiFi to fill in the blurry areas. I have a hotspot utility for my phone, but it might draw a lot of data so I'd rather load up the map info at home.

If anyone finds a map cache utility that eases that job (obviates having to view the data zoomed-in) I'd appreciate knowing about it. I'll keep looking though.