Please post some question if its not clear, I'll do my best.

Hello Guys, I have a project for which I would need some help (first just to know if it's possible, then I would get someone to do it or learn to do it) here is what I need to do :

I have an embeded ECU with a static IP address and subnet mask (10.100.30.200 and 255.255.0.0) and I need to acces this embeded Unit from the internet The problem is my computer need to be in the same subnet mask to be able to connect to it (because of the manufacturer gateway software).

I was thinking of using a tiny embeded Linux computer (like a raspberry pi or other embeded unit)
configure a 3G card to have access to internet
connect my computer and this unit to a VPN (that I can setup in windows)
connect the ECU to an ethernet port of this embeded computer and share this connection to the VPN. (like if the Embeded ECU would be connected to my Computer)

I need to create a setup to test it fast in order to know If we will go forward with the project, I have a raspberry pi with the wlan0 (instead of 3G, for testing it will work) and eth0 working. I tried to setup a quick VPN but There seems to be no "easy way" like we can do in windows (just to test I don't need a whole setup with plenty of certificates... we will work out the security after if we decide to go foward)

Sooooo.. sorry the post is long but here is my question

1 : Is this kind of setup possible?
2 : Do you have a recommendation for a VPN package that can work out fast and well ... (if yo usay openvpn there might be casualties LOL )
3 : Could you recommend me some litterature or anything that could help me setup this "test"

regards.

BTW: I'm an electrical engineer and embeded Chip programmer, I'M not super familiar with linux but I can do stuff and I understand fast.