In fact, the game is quite conciliatory when it comes to avoiding frustration. You'll be able to open a town portal at any time just by hitting the Space bar. No items or inventory space required. And you can actually return to any town at which you've activated a gate. When you're done in town, just go back to the gate and go back to where you opened the portal -- or you can use the gate to travel elsewhere. No cooldowns required, no goat sacrifices, just the Space bar.​