Darren from Edmonton, don't read this until after the 17th.
Vayden, my current adventure arc is outdoors, and it plays fine so far (only one session in so far). Basically, the players start at the top of a mountain (they got there via magic portal) and are working their way down to town. It both allows me open terrain AND to set encounters in the order I want. Additionally, it allows me to set appropriate rests for the players, simply but putting significant distance between encounters.
To start, they arrive in the abandoned temple housing the portal, where they faced a couple of giant spiders. They arrive at night, so they camp down. Not long after dawn they are attacked by some goblin scouts, who saw their campfire the night earlier (this is how far we've gotten). Next session, they will travel down the mountain and stumble on a goblin raiding party's base camp
Night falls and they will likely take a second extended rest.
They then proceed down the mountain and discover an ambush being set by the goblins for an expected caravan. The characters attack and turn the ambush. 5 minutes later, the rest of the raiding party stumbles on them, and I have an epic battle. Players victorious (hopefully), they go to town and level up (XP is planned to take them to level 2).
This also bookends nicely with the in world progression I have - the characters are 3.5 characters who are portalled to a world where things work differently, and thus need to "discover" their new abilities. For the battle with the spiders, they got only at wills, over their first rest they figure out how to use encounter powers and can use them against the scouts and base camp, then they rest during which they figure out their dailies, which they can use against the ambush and the rest of the raiding party.
So, I see out door adventures no more difficult than indoor - you just need to plan it as an adventure.
I plan to use a similar setup after they arrive at town and start adventuring in the environs , setting up planned encounters that seem spontaneous from a plot perspective (hopefully

).
Dr. Ruminahui - shrink with a spear