Internet solution, printing problem Background: 

We have 50+ agents placed at various locations throughout canada. They conduct consumer surveys at departmental stores using our inhouse built iPad app. They record consumer responses and give back to consumer a printout (A4 size) of the consent to participate in survey along with brief summary.

Problem:

Most sites either don't cooperate with our agents to provide them internet or they don't allow our printer (most of our printers are HP LaserJet M130 fw) to be on their network if they let them use the 'Guest' WiFi. For iPad printing both iPad and printer need to be on the same network. Is there any solution to it? We don't want to use cellular internet because of poor coverage and signal strength drops off frequently. So in short our agents need to be independent operative at their site without using their resources.
If you have the option of buying new printers, you can buy a portable Bluetooth printer for them to use. Using Bluetooth you're no longer dependent on any WiFi, and the iPad can use its WiFi to connect to a guest network for internet access or anything you like.

Using a Bluetooth printer is possible because you have an in-house built app. The app would require slight tweaking to support the printer.

For example you could use the HP PJ-763MFI Bluetooth printer which is created for use over Bluetooth with iOS:

https://www.brother.co.uk/mobile-printers/pocket-jet/pj-763mfi

The HP printer support A4/letter size paper.

Another option for smaller paper sizes are the popular Zebra printers that are certified for use over Bluetooth with iOS:

https://www.zebra.com/us/en/products/printers/mobile/mz-series.html

You can also find similar printers from Star and others.