Slightly hidden things that could make Frog's experience a little easier:

The Slime:
He'll give you a quest if you talk to him enough times. Collecting materials for the quest will give you a Bone Sword, a sword with slightly higher attack power that will be useful during the final boss confrontation.

The Wooden Chest:
There's practically infinite health potions to be gained here. Do not pass up this opportunity. Currently, the shop does not allow you to sell the potions to it, but I'd recommend battling to gain money instead of walking across the map a million times. It's 100 gold per walk, versus about 160 to 200 per battle.

The Book:
The book in the house (you know, that house) will give a skill that you can grant to either Frog or his underling, Fish.

The Switches:
They do not do anything. Do not waste your time on them.

The Bed:
It does not heal you, currently. However, there have been issues about Mana usage that have been brought to my attention, and I'm considering implementing a change that will have the bed recover 20 Mana each time you sleep in it.