Any routerboard with USB will work great. If you want to bolt the cell modem in, use the RB411 and a miniPCIe USB only modem check the list under supported hardware for which modems have been tested. 3G works on almost everything. LTE is another story.
Hi!
I would sugest an RB that supports “USB power-reset”
http://wiki.mikrotik.com/wiki/Manual:USB_Features
That way the modem will reboot when RB reboots or if you want to script the modem to reboot
for some reason.
RGDS