That's basically the setup I use. I've attached a picture of my setup below (hope you can see the details). I mounted a piece of acrylic to my OTA on the rings. Then I used Command Strips to mount my RPi, USB hub, Anderson Powerpole hub and dew strip controller to the acrylic plate. So I only have one power cable going to the mount from the power supply and no external USB cables. My intention is to use a similar setup for my other OTAs, making it very easy to change them out.
The RPi I bought is:
The RPi runs the StellarMate OS, which I control over WiFi from my MacBook Pro in the house via RealVNC. Works great!
I also used to use a USB thumb drive (128GB) on the RPi. I have a permanent observatory (SkyShed POD) and would go out in the morning and get the drive. However, over the last couple of months I changed my approach. I not just use the internal SD, which has plenty of space for the night. In the morning, I use FileZilla to transfer the files to my Mac... only takes a couple of minutes. Much simpler and I don't have to run outside first thing in the morning.
If you have any questions, please ask! Good luck!