@TronDC - here's something you can try in Reaper to have louder tracks tonight.
Click on the FX button on the Master fader. Add the X-Comp (multiband compressor). Adjust the width of the bands if desired or leave as default for now. Pick compression ratio or start with something gentle like 2:1. Make sure auto gain make up is checked - this is where the loudness comes in. Lower the vertical bars so that some compression is being applied to the bands. Usually the vertical bars should be somewhat adjacent to each other or else the overall EQ will change. Lower them real far just for fun so you can hear the band get crushed - then, don't do that again
Click to solo the band and then try to find the right level for that band. Repeat for other bands. Tweak vertical bars one last time to taste.
A/B your mix by clicking on the little circle next to the FX button. This will make the FX button turn red indicating it is bypassed. Turn on/off and tweak. If you don't like what you hear, then fix it.
Add FX again and pick a limiter. There are several to choose from. Might want to start with the simple one with the graphical bar showing the reduction. Ensure that the track doesn't exceed (for example) -0.1 db. You could change this to 0 db if you want to "go to 11" - the closer to 0 you get, the greater the chance of artifacts, especially using this basic approach. Make sure the limiter comes after the Xcomp.
Listen to everything and make sure nothing sounds overloaded. If it does, go back and fix it in the Xcomp or elsewhere. When everything's fine, render your file. Tada-if you have done it well there should be no audible distortion.
(Disclaimer - A professional master involves more than this, yada, yada, yada. I'm just trying to get you started.)