Hey,
love the game, but there should be more ways to earn xp.
A few ways could be
gain 25 xp for sending out a scout/geolog
gain 100 xp to rebuild a mine
gain 10 xp for picking up a collectible
gain 250 xp to picking up all collectibles
gain 10 xp per buff on own buildings
gain 25 xp per buff on friends buildings
gain 100 xp per different friends you buff
and properly 100 more events you could do stuff like this for.
these are just some suggestions which would help all to gain a little more xp over time, without having to do all the adventures all the time
This is just a suggestion and you could properly improve this alot more
Regards
Jesper