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.
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.