Which Verizon USB device are you using? I cannot find one that has both WiFi and LTE.
I basically am using the same setup. The Cradlepoint MBR1400 has both wifi bands which has advantages if you are consuming a lot of local bandwidth between systems, cameras, ...
You can probably get by with a 6' USB extension cable - -longer if you use a USB3 cable. If you are trying to get better reception you may want to consider using a Shakespear mast extension tube with a cap on the end. Then shove the USB dongle into the extension tube to hold it up high.
The best part of using USB devices and the CP is you can change it anytime if you are planning on being in an environment with poor coverage from one provider. Cuts down on roaming charges too
I do like your timer idea. It'll prevent the potential for data overload -- like leaving a natural gas bbq on