Druids sound like what you're looking for. Prepared casters, so they have the flexibility you mentioned, and their spell list is filled with exploration and problem-solving spells. They combine things like Charm Person with access to healing and some blaster spells, too. Not to mention the utility that comes with wild-shaping as the situation demands.

For subclasses, you really could pick anything except maybe Spores. Land expands your spell choices even more and regenerates some slots like a wizard, Moon focuses more on wild shapes, Shepherd adds summons into the mix, Dreams some healing and camping utility, Wildfire the usefulness of a familiar who can teleport itself and others, and Stars' special wild shapes can help with maintaining concentration on a utility spell or having things to do in combat that don't require you to dedicate spells prepared to combat much at all.