You need to talk this over with your SP.  Some guys think that because they want to take us on a trip that is payment enough.  You have to think about how much could your friend make if she was home for those 3 days?   All of us have daily rates.  When I am asked to travel, I let my donation for the trip be known and talk about what are the expectations of my time will be.  What are you planning to do on this trip?  Is this a business trip for you where you will be working during the day? Talk all this over before you go so you will both have a great time.  I would not go on a trip with someone who I have not spent time with already.  Have fun..

I've done dozens of them and they have ranged from mulit day fuck fests where we barely came up for air, to having only an hour or two a day of actual sex, and everything in between.

I would echo the sentiment that you simply ask the lady, and see what her wants, needs, and expectations are.

BTW "reasonable" is whatever both sides agree to, and can vary widely between different people.

the last 15 years or so:

We spent nearly all our time together, except that she got a couple of hours here or there to catch up on her email, etc., as did I.  Also on a few of them they were business trips for me, so I needed 6-8 hours during the day to deal with that.

We did 3-4 play time session of 1-2 hours each.  Usually one when we wake up, one early afternoon, one either just before or after evening dinner, and possibly a fourth at bedtime.

My trips have varied from 2 to 5 days.

They have always been with providers I knew very well, and they all went well too.