Sounds like you have a good idea of what you want to do and the technologies, but to start with the basics.
1) I’d suggest a plan with cost options including what ever time its going to cost in time billing. If there is team install project time with two people per visit for safety and x hours traveling time – the costing analysis changes. If you expect to visit the site regularly and can absorb the wireless network planning then it is a different cost structure.
2) First is to identify locations on the ground (sorry sounds basic but sometimes this step gets missed) and the wireless telemetry options.
2) a cellular radio-site survey – probably first on paper, and then if there is the possibilty of a specific cell carrier to organize having that carriers cell phones and then investigate the site options for actual radio signal.
3) if there is a local building with internet then you could consider a point-to-point system. For a local internet need to investigate how to access that network – sometimes it is easy (eg School, sympathetic property owner) other times the network owner (eg County Water Agency) is challenging to get to the right person and permission to install at top of building. Then need to map the Line of Sight for the radio waves – in valleys its tricky.
One narrow valley I installed in – the property owner knew where there was a narrow alley for Verizon Cellphone – its where he could get his Cellphone to work. And we installed a Verizon system in that alley – which was very unique as almost nobody uses Verizon CDMA systems