For your first trip I would recommend staying on the east side of the strip at one of the resorts with a monorail stop. For me part of the fun of Las Vegas is hoping from resort to resort and that can be made easier by using the monorail.
For an inexpensive first visit on the monorail I would stay at The Linq. The monorail stop can be way at the back of the properties but at The Linq it is not that far since the resort is so much smaller.
The Linq will be right by the High Roller and The Linq Promenade which is full of lower priced restaurants.
Being on the monorail will allow you to got as far south as MGM Grand and as far north as The Sahara. From the Sahara stop it is a short walk to The Strat which has a great observation floor 100+ stories high. You might not want to do that walk at night but it is perfectly safe during the day.
The monorail is also a good way to see and visit resorts on the west side of the strip. Ride down to MGM Grand and then take the long walk, it is a long walk from the back of the property to the front, and you can cross the street and have access to Luxor, Excalibur, NY NY, etc.
For your first trip you might also want to pick a day to experience Downtown. There is a little different feel with the downtown resorts and The Fremont Street Experience. Downtown will be quieter during the week and crazier during the weekend. They offer a free concert series so be sure to check their calendar before picking a day to go on your trip if you want to experience or avoid the crowds that come with the free concerts.
Are you wanting to just do Las Vegas, either the strip or downtown, or experiencing more of what nearby Nevada, Arizona, California, and Utah have to offer? If just Las Vegas I would recommend three or four nights max for your first trip. If you want to combine a Las Vegas trip together with stuff nearby I would recommend 3 nights in Las Vegas and three nights elsewhere. We have combined trips with Death Valley, skiing in Brian Head Utah, the Grand Canyon, Antelope Canyon, Sedona, etc, and very soon Zion.
Edited to add:
Want to get your Disney fix while in Las Vegas? Las Vegas has their own Soarin' ride.
https://www.flyoverlasvegas.com/