I've been working for the last few days and I thought I would share an update here.
The main difference between +CGED and +UCELLINFO, at least in my case, is that +UCELLINFO doesn't work on the SARA G350 (2G) modems. Since I am using the Electron 2G model, I am also using +CGED to search for surrounding towers.
I added an option to the electron-troubleshooting app to fire off a +CGED=5 (one shot serving cell and neighbour cells dump) command and I was able to read back the results on the serial port. I received 1 serving cell and 7 neighbor cells. I placed these parameters into Unwired Labs' API and got pretty decent results, but so far they are not any more accurate than using the CellLocate functionality (+ULOC).
In order to decode the signal strength parameter, RxLev, which is a value between 0-63, you will need to reference a 3GPP document called TS 05.08. I found one version here. On page 30 you can see how the values map to RSSI values in dB.
I have noticed if I let the Electron sit for a little while (~minutes) but with an active serial connection, the next time I give a command on the troubleshooting app, I get several (+CIEV: #, #) entries. Referencing the AT command manual, this has something to do with the amount of data in the ublox buffer, but it's not entirely clear to me. Has anyone else seen this behavior?