Requesting help with simple site design

Good afternoon to all,

I have been tasked to investigate a multi-WAN hardware solution - and here I am!
The site I am investigating for has a leased MPLS line as primary data and currently we have no secondary. The idea is to place a secondary WAN connection strictly for backup when the primary fails. Due to the location of the site, we are severely limited to our secondary media choice; we will be going the cellular route as the coverage looks to be decent and LTE is available.
I am looking to use the Balance 310 utilizing the Drop-In mode between ISP router and our firewall.
As far as hooking cellular WAN to the Balance 310, I am open to suggestions. Simple USB antenna from the carrier?
SIM card in another Peplink product (MAX series or the like)?
Once the details are squared on paper, we will being pulling the trigger on this soonest.
Thanks in advance for any advice and ideas.

Good call on the drop-in mode with the 310. Your lowest cost option would be a simple USB modem from the carrier but this isn’t the route I would take. USB modems can and do lockup from time to time and a physical reset is needed to restore connectivity. It would also most likely be carrier locked and no easy/reliable way of going with external antennas.

I would take a MAX BR1 and get a data plan & SIM card from your choice of carriers and feed the 310 via Ethernet.

Thanks!

Excellent - thanks for the response.
That is essentially what I had come up with as well - just wanted to make sure I wasn’t missing anything obvious. I appreciate your time.
Anyone else thinking a different route?