Go read the spoiler if you want the answer right away.
Nah bro, i recommend that you focus on training your character the guy to unlock skills like human wall and life steal cause basically you're the tank of the team but you also need a decent damage to duo your way to the forest in the early game there for unlock the female character skills set first to unlock their full potential.
Best tip: invest more in stamina early game why? To farm for all stats 1+ you will need stamina for the cost -5 in every battle or exploration in the forest or normal tournaments. Early game you always run out of stamina right away 30 is so low and practice cost about -20 sorry if the cost is off, yeah i forgot cause, i finished it already i'm around at 200 stamina max and already killed the demon lord in two attempts but i hope you get it in one attempt adventurer.
Spoiler: this is the onsen part if you really want
After that in the days around 70 to 90 days is very important cause the onsen part is basically where the tournament of hero for who will be the one to earn the title of hero's party in order to be able to challenge the demon lord which is the final quest.
Basically the onsen part is just a vacation only once and not a place to be able repeated visit if you really want you need to grind for it.