I think these three steps may solve your problem:
1. Set up a project with the setting as you want them.
2. Save this project.
3. Set it as default new project.
If you want a default FX chain for all new tracks, set up a default track template in a similar way.
These things, and much more, are described in the excellent User Guide, just click the "Download user guide" link on
http://reaper.fm/