Hi Jake. Long time no talk to. Yes the XTS3000 can be programmed for conventional frequencies to receive only (no transmit). I'm assuming that you are talking about listening to either the PD or Sheriff for the Union County area.
The largest factor is that Motorola radios can be very difficult to program. They require that you add everything from scratch. Then you need to program the scan groups and associate them with the personalities (channels) you create. It's not as easy to program as a scanner is.
The other thing to consider is that the XTS3000 is a single band radio only. So if you wanted to listen to the sheriff, you'd need a UHF version of the radio. You would not be able to program the frequencies for the FD since they are VHF. Also you will only be able to have 10 scanning channels (as I remember).
Another thing to consider is that you can't change them on the fly. You'll be locked into the frequencies you program into the radio.
Finally you'll need a specific software, and RIB or special program cable, and a certain level of PC that can accept the CPS software for that generation.
Honestly Jake, your best bet is to stick with a scanner. While it may be "cool" to have a Motorola, they can be awfully complicated, and not nearly as flexible as a scanner. But I know you like learning new things and it can be a fun project for you as long as you have the patience to learn.