This is what I ordered from the RAKwireless store:
https://store.rakwireless.com/products/wisblock-meshtastic-starter-kit (pick the correct frequency for your region)
https://store.rakwireless.com/products/rak1921-oled-display-panel
https://store.rakwireless.com/products/ipex-to-sma-connector

RAKwireless also has GPS modules if you want GPS.

I bought these parts locally:
- LoRa antenna with RP-SMA connector
- 3.7V LiPo battery with JST-PH connector

3D printed case:
I used this one: https://www.printables.com/model/286657-rak19007rak5005-case-for-meshtastic
The Printables page for the 3D printed case has several options for different styles of batteries as well as instructions for assembling.