You know your "friend" so well

My advice to your "friend":
Already spent time and money to plan for the trip + the friend seems harmless then don't waste lor.

Friendship with opposite gender is fine but do all you can to respect the boundaries.
1. If "friend" already has concerns "might not be able to resist the temptation of the foreign chic as it's still a foreign chic.", then make sure to keep on full sanity and alertness. That means no alcohol, fap if horny (because post-nut clarity?) etc.

2. Don't engage in physical touch. You cannot control others but you can make sure you don't be the one initiating any. Shake hand is ok but nobody in casual setting still shakes hand right? Lol

3. Don't owe her anything. If she treats you...r friend the local attraction tickets (maybe there's discount for locals?) then treat her back with a meal as thanks.

4. Don't go to her house regardless of reasons.