I have a Samsung tablet that I've used to mirror downloaded content to a Roku streaming stick with no issues at home where I have WiFI and internet access. However I have a travel trailer with no access to the internet. Is it feasible for me to acquire a router and setup a local wifi network that would enable mirroring without internet access. Sorry if this issue has been addressed before.
It should work in theory, as it's mainly necessary to ensure both devices are connected to the same network (IP address range, netmask, DNS settings). The problem might be getting the Roku to connect to the network when there's no Internet access. I suggest setting your mobile network SSID name and password as the same as you have in your home. Connect the Roku to that network successfully, then go into your trailer and test it on that network. It should connect without issue, and then be able to access anything on the trailer network.
Dan Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.