All of this depends on what methods you're keen on using and whether or not that method is sacred with regards to the end result.
If you're set on just recording takes of jams with the pedals/synth/scrap metals then yeah, you'll struggle getting the best out of things with no amp. Especially where the contact mic'd stuff is concerned.
If your concern, however, is just to make good sounding work then you have a lot of options. You could take initial recordings that may sound a bit weak and lacking and process them through your pedals again. You could record to tape initially - which will be much kinder to you when pushed into the red than if you did so digitally - and then further process that tape or simply line it in and transfer it to your computer.
Don't forget as well that even if you did have the option of a loud amp, there is a huge difference between what you'll hear performing vs what you'll get just by shoving some shitty mic in front of the speaker. Getting good recordings from this kind of setup is something that takes its own kind of practice and trial/error too.
The ideal way to make and record sound is to have a range of options so, in my opinion, the answer is really somewhere in the middle of all this. As ever, the key should be to experiment and practice within what you have rather than worry too much about what you don't have.
