Compared to a lot of cities, Denver doesn't have many areas to avoid. There are spots in Aurora that are kinda crappy, but some of the best food (and manatee hour!). Overall though, you're not going to run into areas that are extremely dangerous by accident. Down by the Rescue Mission (southish from Coors Field a few blocks) there tends to be a lot of homeless camps. I wouldn't recommend hanging out there, but it is pretty easy to spot and avoid... or walk by. 16th Street Mall (a place you'll likely head to) has had some spurts of those camps lately too. East Colfax into Aurora can get rough. But really... keep a good head. If you rent a car, don't leave your belongings visible (smash and grabs are probably the most common crime). You'll likely be fine. This isn't a Milwaukee/DC/Baltimore type city where it can get rough and dangerous quickly. Most of the crime is property crime and theft.
Downtown Denver is rather clean and walkable downtown for a western US city, but compared to east coast or European cities, it isn't that walkable (but it is a lot cleaner than both). You can walk around LoDo or 16th St Mall pretty easily. If you're walking or using public transportation, you'll be limited by the interstate and just pure distance... Denver has a lot of sprawl. The Highlands area is up and coming with a lot of good food and breweries. LoDo (basically Coors Field area) is filled with bars, clubs, and food. Most of the food follows US trends. So you'll find trendy fusion restaurants and such just like a lot of other cities. There is bound to be a decent restaurant of almost any type of cuisine you want. The Buckhorn Exchange isn't the best restaurant in Denver, but it is a local staple and flair. One of the best Ethiopian places I've ever had outside of Minnesota is on East Colfax. Guard and Grace is a great modern steakhouse, legitimately $200+ every time I go with my wife though. Tavernetta is excellent Italian food. But you can find good pizzas of different types (Blue Pan is a favorite of mine). Denver is big transplant city and the food reflects that. Plenty of variety, not a whole lot of local flair... which is why I'd recommend Buckhorn. When you go, order your friend the Rocky Mountain Oysters. I'd also recommend Linger too... more vibes than high end quality.
If you're a beer person, Denver has one of the best craft beer scenes in the world. There are many world class breweries throughout the city. Everything from Czech lagers, to the hoppiest of IPAs to sours that give Belgium a run. You can find anything you want there... you just may have to trot around the the city to get to some.
For lodging, if you're going to stick downtown... all the normal big names are there and probably fine. The Brown Palace is an interesting local hotel and well located. I'm sure there is an abundance of AirBnBs too that'd be fine. If you could get by the river, you'd also be in a good spot there.
Other things to do... if there is a show as Red Rocks you're at all interested in, it is worth it. Epic place to see any band. For golf, there are a ton of good options. I really like Fox Hollow by Red Rocks. City Park (nearish to downtown) is fun with some obvious space limitations. Fossil Trace is my favorite that I've played. I've never been lucky enough to play Arrowhead, but I'm sure somebody here has. Lots of good hiking and outdoor stuff on the western side of town. Just keep your eyes out for rattlesnakes as they are pretty common on those trails. Meow Wolf is an interesting experience, especially if you partake in other things prior.
And... above all else... Shotgun Willies. You're bound to see former Avs legend Tyler Arnason putting a single mother through college. If not, you can at least score some baby laxative laced with cocaine.