You need to rest 6 hours for an extended rest. That is mostly just a night's sleep (4 sleep, one keeps guard = 8 hours total camping overnight).
The rules also state that you can only benefit from an extended rest again when 12 hours have passed from the previous extended rest.
So, anything that happens within the same traveling day is going to be fought with the same resource pool (daily powers, action points).
If you have a week of overland travel, then a single encounter in the middle might need special attention to make it a challenging one.
One thing you can also use is to have some skill challenges for travel, which consume healing surges (exhaustion) and possibly even require everyone to expend a daily power or something if the party fails the challenge.
The rules also state that you can only benefit from an extended rest again when 12 hours have passed from the previous extended rest.
So, anything that happens within the same traveling day is going to be fought with the same resource pool (daily powers, action points).
If you have a week of overland travel, then a single encounter in the middle might need special attention to make it a challenging one.
One thing you can also use is to have some skill challenges for travel, which consume healing surges (exhaustion) and possibly even require everyone to expend a daily power or something if the party fails the challenge.