I thought CP/M and the various tools on a tiny computer like the Teensy 3.6 would be a perfect low powered non-Internet computer various projects and to be portable. However I still needed a terminal to use CP/M and I wanted some minimal graphic capability too. In search of a small dumb terminal board I stumbled in the the world of Maximite HERE and MMBasic created by Geoff the genius!
I am now using a Maximite clone (CGCOLORMAX2). It can drive a VGA or composite display directly with great graphics along with a SD card based flash file system, real-time clock and I/O capability. Recently I have been digging into the power of Geoff's MMBasic that runs on the CGCOLORMAX2 (which uses a PIC32). Even though it is a single precision version of BASIC I have had great success in porting some mathematically intensive astronomy programs.
I have setup my CGCOLORMAX2 to run with a small 4.3 TFT LCD composite display used for backup cameras. The only thing else needed is a PS2 keyboard and DC power to run the board and the monitor (e.g. 12 volts). This setup is running great so far and will do some power consumption tests soon to size the battery pack to make this portable.