When a party spends a game week training at a secret master area, they can

Learn a new skill

Upgrade wounds or fatigue

What are the limitations here. The rule book is not clear on this. Each hero can learn up to 1 skill. Each hero can upgrade wounds +4 or Fatigue +2, only once per campaign level and only one or the other (wound/fatigue) but not both.

The question is can a hero learn a skill AND upgrade wounds or fatigue in the same week or is it one or the other?

Also, do secret master areas work like cities where they can purchase trait upgrades here too based on the skill availibilities (melee, ranged, wizardy)?

Bravo McWilley said:

The hero may only learn one upgrade per week. So either a skill or a stat upgrade, not both. This is similar to being in a city and doing a train action. In that case, you may also only do one upgrade. ("Train" section of rules, page 23.)

Bravo McWilley said:

Yes, see the "Trait upgrade" secion of the rules, page 23:

Heroes can improve their traits when they go to a Training Ground in the training circumstance (see “The Training Ground” on page 22), or when the party takes a game week Recuperate/Train action on a Secret Master Area (see “Secret Training” on page 23).