Well, for a 50 mile trip, i think the boxster will be fine just as long as you arent too over weight, can work the auto climate control and arent too tall.
Reason being... Weight, that can be a factor because the seats will feel uncomfortible after awhile, jabbing your love handles and your thighs slightly. I was 255lbs and i was fustrated everyday with how the seats felt so i went on a diet and lost 55lbs. just so i can drive my boxster without wanting to constantly drive it into a tree in fustration.... same fustration you get when your argueing with your wife and shes being stuborn.
Auto Climate control... If you get hot or easily warm while driving, You need to know what temp you can equalize the interior temps so you dont get hot and fustrated... usually 69 does it for me.
and height... if your too tall, that can be a problem since there are no back seats, That means, Firewall against your back which mean you cannot lean the seat too far back before hitting the firewall. Im about 5'11 and found a comfy seat position but any taller and i dont know weather i would be able to find a comfy position but thats all relative to the driver and there seat positions.