I was recently in your same situation. Needed a tripod that would be mostly lugged around in a padded bag on four wheeler or in my truck back seat. I wound up with a Manfrotto 055 XPRO3 aluminum legs and a 501 fluid video head. While I know this set-up doesn't fit your budget, I have to applaud it's incredible craftsmanship. I think I paid $400 with a $40 mail in rebate so the total came to around $360. Please forgive me if $160 over budget is not worth talking about.
The legs are very strong and sturdy. Something I had to see to believe. Thankfully I went to a high end camera store and got to see things in person before purchasing. I would have made an uninformed choice had I not.
Once I was there, I would have pursued carbon fiber legs but all they really offered was a pound less weight for twice the price. Folks say they reduce vibration but I don't see where if an aluminum base is vibrating that a carbon fiber would have solved all the issues. Something that's causing a quality tripod to transfer vibration to the glass will make anything shake no matter what material it is. Common causes of shake are wind or an unsteady ground such as a fishing dock or pier wobbling in wave action and from people's footsteps.
Not only are the legs strong, but very versatile and user friendly. The flip locks are a cinch, you won't want twist locks if you move around much at all. Another major selling point to me was the feature to extend the center piece all the way up and then flip it 90° to the side. This allows me to sit in a box blind with the tripod off to the side and not in front of me, yet the scope is still right in front of me for easy glassing. If I want to raise my gun, I simply twist the tripod and the scope is rotated away from me so the shooting rest is clear now. Something to think about if you hunt from box blinds.
But the head is what set the whole deal together for me. That thing can handle up to an 11 pound camera. It will pan/tilt with the greatest of ease and stop on a dime and STAY THERE when you let go. No having to loosen and retighten or anything like that. I say if anything, don't skimp on the head. My spotting scope was nearly useless when I was trying to use it on my wife's plastic tripod and cheapo ball head that came as a freebie with the purchase of a Canon DSLR.
Still before visiting the Houston Camera Exchange, I called and spoke with B&H Photo for recommendation a lot as well. If I ever have a chance to use my scope in Alaska or New Mexico on some extravagant multi-day hiking hunts I will pursue a lighter tripod. I was recommended from B&H to look a Sirui T-1205X 5-Section Carbon Fiber Tripod for a quality tripod which is a tad under 2 pounds. That will pack around much easier.