Whoaaaa! '. . . under no circumstances can she ride 150' . . .
Give your wife/stoker some credit!
What's wrong with riding 150 miles over a 2-day period?
Think back a bit! How long did it take you to work up to 150 miles in one day?
Bet there's a few things you can do better than you . . .
Patience/practice/partnership is what tandeming/marriage is all about!