I backpack. Have not bikepacked yet. But I've been moving to lightweight backpacking gear. I use a down quilt instead of a sleeping bag (compresses smaller and is lighter than most bags), and have embraced the new inflatable sleeping pads. Not self-inflating. That's so 80s/90s.
The insulation offered by your sleeping pad is extremely important for quilt-use in the high Sierra, but it cannot hurt for lower levels. Plus these new pads come in 2-3inch thicknesses, weigh around a pound, and roll up into a small package. I use a Thermarest Neo Xtherm, full length. It is mighty comfortable. Thermarest (which i highly recommend) offer cheaper but slightly heavier options. The Neo line of pads offer reflective foiling inside that actually reflects your body's heat. I can feel the warmth simply trying it out on my living room floor. The earlier models were crinkly, but they have quieted down as designs have improved, especially if you do not go with the ultra lightweight models (Neo Air).
A down quilt offers the choice of using it like a blanket, you can allow your legs to spread out and manage warmth. plus at 1-1.5lbs, extremely lightweight.
A good night's sleep is so important, especially at my 52-year old age. I've seen yoga mats. I think they would offer almost nothing for comfort.
eric/fresno, ca.