Depending on the testbed's location, there will be a couple of environmental requirements. AWMN has extensive experience with installing nodes on TV towers in the greek mountains.
Lessons learned from the greek mountains.
Another requirement for remote nodes will be that it will be hard to get there to reboot or do maintenance work in case of failures. For remote reboots, there might be a solution to connect them to a receiver for APRS. This way, an APRS packet could trigger a reboot.