stamina can be renewed infinitely with 2 red-nules, a caffiene+, and 3 meditate/yogas.
to do this, use cards in this order (assuming you have all of these cards ready):
caffiene+, red-nule, red-nule, meditate/yoga, caffiene+, red-nule, meditate/yoga
A couple recommendations:
The supermonkey only being useable after a certain amount of rounds (somewhere around round 10-12)
Road spikes have fewer spikes, or cost more