Im kinda in the similar boat. While I do aknowledge the awesomeness of plugins I just want to record what I and my gear sounds like, not a hundred plugins.
It can be very easy to use Reaper just for recording, you don't have to use plugins or more advanced features.
Simple Reaper tutorial
Setup the connections
First connect your audio interface to the computer and your bass as described in the manual. Depending on the operating system, you may or may not have to install drivers. The manual should clarify it.
Also make sure that the input / volume levels of your audio interface are set to a quarter or so level, you can always turn them up.
Preparation: setup the audio interface (only required once)
1. Start Reaper and press CTRL+P (or go to the menubar Options | Preferences)
2. In the left bar, Scroll to Audio | Device
3. Select Audio System, usually ASIO is preferred for best performance
4. Select the Audio Driver. For my interface it is M-Audio Delta Asio, yours should be the one with the name of your audio interface
5. Make sure the checkbox Enable Inputs is checked and select the first 1 or 2 input(s)
6. Select the Output range, usually the first 2 outputs
Recording:
1. Start Reaper and press CTRL+T (or from the menubar Track | Insert new track)
2. Press the red circle Record arm/disarm button on the top left of track 1
3. Play your bass and you should see the meter bar(s) moving. You might have to click the Speaker icon right next to the Record button to toggle the Record Monitoring options to be able to hear the sound from the audio interface.
4. Press CTRL+R (or click the Record button at the bottom left) and Reaper starts recording
5. Press CTRL+R again (or the Record button) to stop recording
6. Press the SPACEBAR (or Play button) to hear your recording (click with the mouse in the right panel to set the cursor at the playback/recording position)
7. Press CTRL+S (or click the Save Button or menu File | Save project) to save your project
That's it...
BTW: I'm not forcing anyone to any specific DAW (in fact, I use several...), I think you should use what works best for you.
But recording in Reaper can be rather simple, it takes me just a couple of clicks to start recording.