You could stay at the Hacienda along US 93 less than 5 miles from Hoover Dam. http://www.haciendaonline.com/hotel.html
There is not too much to see north of Valley of Fire until you get to St. George UT.
There is a paved road that goes up the west side of Lake Meade that gets you to Valley of Fire without going back into LV.
Have you booked your flights already?
Allegiant Airlines does have some bargains when you combine your airfare with a a rental car, show tickets or a hotel.
If you find the time try to get an hour or 2 in Bryce Canyon in addition to Zion.

You might think of Henderson, just south of LV.

Not really touristy. Here are a few links.

http://www.cityofhenderson.com/

http://www.visithenderson.com/

There is really no place to stay near Valley of Fire State Park unless maybe there is something near Overton/Lake Mead.

You might go north on the 15 freeway up to Mesquite Nevada where there are a couple of casino hotels with restaurants. Better yet, go north towards St George or Zion, will make for a long day of driving but how nice to wake up near Zion two mornngs in a row.

I would think you'd be finished at Tillman Bridge and Hoover Dam by 1pm, have lunch and then see Valley of Fire from 2 to 6pm...leaving you plenty of time to have a light dinner in Mesquite and then continue north to Utah.

I would forget Valley of fire and concentrate on visiting Zion and Bryce parks.Paul

Yoe mention no hiking due to physical issues. Does that mean walking is an issue, strenuous walking or what? Makes a difference.

I agree with tovarich.

I would concentrate on Zion & Bryce Canyon.

I Bryce you can stop at several viewpoints and walk along the rim. You don't have to do long hikes. Depending upon the physical issues you could walk down at Sunset Point for about 100 yards just to get a feel of being down in the hoodoos. Then walk back up taking your time. In any case, walking the rim is beautiful.

In Zion it also depends on physical condition. I believe the Riverside Walk is wheelchair friendly and the scenery is spectacular.

I agree with Myer and tovarich about skipping (or maybe just driving through) Valley of Fire if it would give you more time at Zion and/or Bryce Canyon. You don't mention Bryce in your OP but if at all possible you should try to get there... these two national parks are amazing, unlike anything else in the U.S.

Agree with wrongfoot. Head up I-15 and go to Zion first and perhaps Bryce Canyon. On the way back, if you have the time, turn off I-15 to Valley of Fire. Coming out the east side of VOF, will bring you to the Northshore road. http://www.takemytrip.com/07zion/07_22a.htm
Out in the middle of nowhere you will turn left on the road that goes south on the west shore of Lake Meade. When you get to US 93, turn left to go see Hoover Dam.
If you don't make the left turn, you will come back into LV on Lake Meade Blvd. Pack the sunscreen. I got burned while swimming in Lake Meade.

Red Rock Canyon is only about 20 minutes from the Strip - and has a nice visitor's center and is easy to drive, stopping where you want for walks.

And while I think Valley of Fire is quite interesting, and would like to camp out there for a night the next time we visit, I would also suggest you consider skipping it this trip and get over to Zion as soon as you can, which is about 3 hours from Las Vegas.

If you feel up for more driving, Bryce is only about 85 miles beyond Zion - two fairly easy hours of driving, unless of course, you get stuck behind some caravan of campers/SUV's.

You might even consider "going for it" the first day (you could go up the freeway and in from there vis a vis going up from Zion) - and go all the way to Bryce, and then the 2nd night - come back to Zion - which puts you closer for the return trip to Las Vegas.

The Hoodoos at Bryce are very unique - as it has a great sunrise - but if you had to choose - I think Zion has more things to offer.

However - if you can do both - the more the merrier.

Thank you to everyone for your helpful replies. I think I will do some more research and figure a way to include Bryce. I like the idea of going all the way to Bryce and then seeing the other places on the way back. Would anyone have any suggestions on where to stay between Bryce and Zion? When I mentioned physical limitations I should have been more clear. Small walks are ok but not long hikes. Again thank you for the information and if anyone has any other suggestions or helpful ideas I would love to hear them. Thank you.

Although I have been in the area twice, staying once near Zion and once near Bryce, I don't recall anything between them. Stayed last Sept. in a motel near Tropic that I don't particularly recommend and I doubt I'd suggest Ruby's at Bryce based on lunch there a few years ago (not that food quality has much to do with rooms). You might try for a room inside the park at Bryce. (We did have a surprisingly good dinner there last fall, though I'm sure the rooms are typical park service.)

If it were me, I'd beeline straight to Zion ASAP. If your plane arrives really late, you might spend the night in N. Las Vegas and head to Zion the next day. If you want to drive a little after you arrive, it's a bit over 2 hrs. to St. George, which has plenty of hotels. Don't recall any accommodations to speak of between N. Vegas and St. G. except maybe a casino hotel here and there. Quite a few hotels in Springdale, UT, just outside the park and some pretty good restaurants; both hotel quality and food is better in Springdale than anything in Bryce or Tropic. A few years ago we stayed at the Desert Pearl, with a patio opening on the lawn beside the river, on recommendations of people on this forum and liked it. Then maybe I'd do Bryce as a day trip from Zion; if you check the map you'll see that you have to return to Vegas through that general vicinity anyway, so you could spend the second night back in Springdale. If you wanted to take a different route back from Bryce and it would still be daylight, you could take Rt. 14, which is quite scenic and passes Cedar Breaks NM, which has some terrain that resembles Bryce, including canyons with hoodoos. Could spend the night in Cedar City or go on to St. George. Also just south of the intersection of 14 and I-15 there is a section of Zion, Kolob Canyon, that isn't accessible from the rest of the park, I don't believe. We didn't find it spectacular but it's right off the Interstate and worth 45 min. to drive thorough.