We are a family of four with kids age 10 and 7. Travelling from upstate NY and are looking to plan a trip over the summer for up to 10 days. Would love advice on an itinerary. Initial thought was to fly to Vegas, maybe spend a night there and then rent a car, see some sites out west and then end the trip in Long Beach for a short cruise. Open to ideas!

Skip the cruise! Land at Las Vegas and rent the car. You can easily spend 9-10 days doing the circle route that includes the southern Utah parks, Monument Valley, South Rim of the Grand Canyon and Hoover dam.
Spend your last night in or near LV before flying out.
The Fremont Street Experience is worth about 2 hours in the evening to witness the overhead light display and the 62+ lb. nugget at the Golden Nugget. In the daytime, there is a zip line for the kids under the light display.

You are visiting in Summer and it will be bloody <RED>HOT</RED> in the desert.

With just 10 days you do not have time for Zion/Bryce, the Grand Canyon, Vegas . . . AND a cruise (or anything in CA for that matter)

So what sorts of things do you hope to see/do?

W/ 10 days you could do a short loop in SoCal (with or without theme parks) and a 3 day cruise (which mostly aren't geared to kids.)

Or you could do a very hot loop Vegas > the GC > Bryce > Zion > Vegas.

Or there are other combos like Vegas/LA/San Diego, etc.

Mostly depends on what you want out of the trip and your tolerance for heat.

I'd skip the cruise and the SW and Vegas (not kid friendly) and fly to LA, stay for 3 days then drive Highway 1 with two overnights in Pismo Beach and Monterey, then 3 nights San Francisco, leaving you with 2 spare nights.
Or do LA, San Diego and Disneyland and California Adventure. If you do visit San Diego be sure and check the dates Comic Con is on in July, as hotel rates near downtown go sky high.

Are you saying you have 10 days for the southwest portion of the trip before starting the cruise - or does the 10 days need to include travel to California and days for the cruise?

I personally would fly into Vegas but not spend much time there at all. I would recommend renting a car and checking out Zion - Bryce - and then either Torrey/Capitol Reef or the Grand Canyon south rim - back to Las Vegas. I would save the cruise and California for another trip.

>> I would save the cruise and California for another trip.