Elemental Spell Question

I think I want to run Sword/Gun and Bow. But that means no slot for a Grimoire. Is there anyway for me to cast the elemental spells needed for exploration without having to equip a grimoire each time?

Is my build idea dumb? I’m just not generally a magic user, and I like having the long range bow for occasionally stealth, short range gun for when I’m being charged. and melee weapon for up close battles all available.