We are having same thing; people slowly migrating away from CBs. I currently have some of the Baeofeng radios as they can utilize FRS/GMRS as well as licensed HAM use on 2m and 440cm. Those do not allow attachment to external speaker that I have been able to figure out; but they are cheap and not a worry if I don't get it back or it gets run over on trail.
As for the GPS, I have been using my phone and iPad for last couple years and just keeping the Garmin handheld for hiking/hunting. I have been using Viewranger app the most and Gaia GPS app recently. There are features of both I like and both require a membership to be able to download maps for offline use. I have a membership with viewranger as I like their maps better and it has street maps, Topo, and satellite that you can use. As long as your phone/tablet has GPS you won't need any external antenna. I ran into same problem with the garmin screen just being to small for my eyes age.
PS: love RAM mounts and have them for everything.
05 TJ Rubicon, 6 spd, RE 4.5 long arm, 35s and other mods