I missed the start of the thread. However, I did a coast-to-coast trip
in a strictly VFR only Cessna 140.

Three observations:
It's no harder to plan than any other cross country
Be flexible (you have a wide choice of routes when doing such a long
trip - fly where the weather is best)
Make sure you have contingencies for maintenance. My trip involved
100 hours of flying. This means at least two maintenance days assuming
nothing broke.

On the maintenance angle, fortunately my trip was purely for the fun of
exploring - so I could plan to be back at base for scheduled
maintenance. I still had the generator fail halfway through though -
fortunately, I found a shop where we could rebuild the thing there and
then.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"