If you do go on the occasional longer distance then there are solutions by strapping another 25 liter tank in the back seat and using an electrical pump or gravity to transfer fuel from one to the other. I'mnot sure how you would be able to see if it is working though? twisting in the seat, or maybe a mirror?
Besides, half the fun of the long distance trip is to fly with your mates and to land every hour or so for a chat, smoke, bum break, piddle
Use this time to top up the tank.