I'm planning on spending an entire day exploring the gorge area using Portland as a base and wonder what would be the best route, best places to stop, etc. I've also seen mention of continuing around the Mt Hood area and looping back to Portland. Is this possible or reasonable in a day?

You can do the loop in a day, Portland, gorge, Mt. Hood, back to Portland. Though I don't feel it doesn't give the option of truly stopping and exploring. If you want to explore --Hood River is a fun town, there are good hikes around Multnomah falls area, the old historic columbia highway is a (slow at times) beautiful drive. As a native I recommend you decide if you just want to visit the gorge or see Mt. hood as well. It can be done in a day, but as a local I would rather spend time hanging out in the gorge and not feeling a need to get around Mt. Hood and back to Portland. Good luck and happy travels! Autumn is a beautiful season to visit the area.

If you're planning any serious hiking in the Gorge, best to just stay in and explore that area. But, if it's just the few short walks to waterfalls, you could fit in the loop around Mt. Hood. The route from Portland would be the Old Columbia River Highway east to where you're forced onto I-84. At Hood River, head south on hwy 35, up the east side of Mt. Hood to hwy 26, then loop back into Portland. The one "must see" on Mt. Hood is Timberline Lodge.

In Portland today and tomorrow only. Actually here for a football game in Corvallis, so will only have a few hours in the morning. Can I see any of the gorge in a few hours? Where best to see and what route?

My favorite drive in the Columbia River Gorge is going west on WA 14 from Marryhill to Washouhal. It gives the best views of the Gorge and, on a clear day, Mt. Hood.

Driving south on OR 35 there are great views of Mt. Hood and, driving north on this highway, you will see Mt. Adams, in WA.

In my opinion, the drive on OR 26 between Portland and Timberline Lodge is neither scenic nor pleasant.

Mulnomah Fall, the "grandaddy" of them all, is only 31 miles east of the city, Leburta. So yes, if you don't lurk too long at any one place, you can see a bunch in a couple hours. Besides Multnomah, I'd particularly recommend Wahkeena (short walk up to the falls), and Bridal Veil.

Take I-84 east to exit 22, then head uphill to pick up the Historic Columbia River Highway. After Multnomah Falls, either turn around, or continue east for another 4+/- miles to a junction with I-84 for the return to Portland.

Oh, and GO BEAVS!!

Hey Happytrailstoyou and everyone else-
Thanks and I've deceided not to make the complete loop around Mt Hood and back hwy 26. Would it work to drive Historic Columbia River to Hood River then cross over to WA 14 for the return trip?
I'm also wondering if it's worthwhile driving south on 35 a few miles from Hood River to see the valley/wineries/fruitloop area etc? Wineries etc worth seeing?

Yes, you can cross and take 14 back over and it is quite scenic. But I would highly encourage you to take HWY 35 then 26 for a bit and see Timberline Lodge. It would be a longer day doing this, but you can do the gorge, then continue to 35/26 to Timberline and then backtrack to Hood River and then to 14 back to Portland.

If this were me, however, I would just stick to the loop as it saves time and I enjoy it.

Thanks for your advice. Didn't have time to see the gorge and University of Hawaii lost big time to OSU. All in all, not a good day. Will save this for next time though. Portland is a great little town!