I like my wagon, and wouldn't hesitate to drive it anywhere. Having said that, I would not drive it as much as you are talking about and trust it. You have too much riding on things not to be using a newer vehicle.
Now, you could get a Benz and use it part of the time, but a Japanese car is going to be the most reliable, get good gas mileage and have a warranty. Regular is cheaper also.
Now, look out, you are fixing to get a carpet-bombing of folks stating how they wouldn't hesitate to use their Benz, but read a few pages of these threads and see if you want to roll the dice....

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John