I'm wondering if there is any way to get your spells back (other than the short rest) while you're in one of the adventure areas. I'm finding that it is nearly impossible to win more than one battle in an area since I end up using my spells in the first encounter and have no way to get them back during the second one. I'm currently in the ruined tower and I'm finding it pretty impossible to beat the creatures in it since I effectively have no arcane or divine spells. I.e. I'm fighting with one hand tied behind my back.
If not, then I really think that this is a game design flaw as it makes the game incredibly frustrating and not at all fun to play.
no
and no it is not a design flaw. It prevents "camp spamming", which is a cheezy tactic.
Get better at the game. You wont need more campfires.
which tower specifically are you in?
the one with the floating books? There is a campfire for you to use, before you enter the final room to fight the Soraks.
One essential feature of Solasta is resource management. You have to weigh your limited ability usage against the chance you'll need them in future fights. In most fights you probably don't want to use more than 1/3 of a caster's spells.
There are some things to offset this: you can use consumables (spell scrolls, poisons, oils, potions) to buff your party, all spellcasters have cantrips which they can always cast, sneaking to get an important surprise attacks against the enemy, and of course there's changing the difficulty if you really need to get past a single fight. Then, in the future, you can go forward with more of an idea about the resource management between long rest sites part of the game ^_^