I would say that if you have night and/or instrument rating then this helps get the hours done much easier.
I did 200 hours in one month flying around the states in a PA28. Hard work? Sure, but also a lot of fun. Did quite a bit of sightseeing too. Try and find people to fly with you if you can, just to make it a more enjoyable experience. Or arrange to fly with another hour builder (both of you with your own aircraft).
The 200 hours was no real problem, there were a couple of days of bad weather but if you are open minded and flexible you can get it done.
I hired from Air Desert Pacific in California, they have very good "block hour" deals.
I got a PA28 straight out of the hangar with 100 hours to fly before the next mandatory check.
Top tips.
Have a Rand McNally road map with you to choose good places to go.
Get the plane organised inside, with everything you are going to need in an easy to find place. Such as maps, approach plates, etc.
Get one of those huge AOPA telephone directory sized guides. They have all the airports listed along with accommodation, which FBOs have free accommodation/ courtesy cars, opening hours, etc.
Plan a good adventure!
Get up early. Watch the Weather Channel often. Never rush yourself. Plan the next day's flight the evening before.
I used to get up early and be flying by 8am. Get a routine going -
check weather channel, get to airport, ring 1-800-WX-BRIEF for latest weather and NOTAMs and file your flight plan (always, whether VFR or not I would). Go to aircraft, check it over, check fuel.
Go!
Fly for 2-3 hours, more if you want. Perhaps fly from A to C via B for added interest. Stop at an airport for a drink and a break before continuing. Get update on weather.
Arrive somewhere interesting and borrow courtesy car from FBO. Go visit the sights, have lunch, etc. Late afternoon (or evening if you have night rating) set off for another 3 hours or so flying, perhaps two 2 hour legs with a break in between.
This way you get to see a lot of airports. Many times in the evening we would go out. Check out what you want to do sightseeing wise then find the nearest airport. You'd be surprised how much you can fit into a day.
You can fly across America and back in not too many hours, even in a Cherokee.
Final tip. Don't get blase about it. Question your actions often. You may have done the same thing the last 2 weeks but that doesn't mean you won't make an error today. Always double check weather, fuel and weight and balance.
You will learn an immense amount if you do it this way and also have a hell of a lot of fun!!
If anyone wants any specific info let me know and I can e-mail you.