Purchasing single family house in the Denver area

[Jay Gil]

I live in California and am looking into purchasing a single family house in the Denver area. I have shortlisted 3 Denver suburbs(Littleton, Highlands Ranch and Parker).  I identified these suburbs primarily because of good schools and the fact that I should be able to find a property under 600k. The house will be managed by a property management company. The goal is to hold on to the house long term(10+ years and until it is fully paid off). Since will be my first investment property purchase, I was wondering if someone could provide me feedback on:

1. Would houses in these cities potentially hold their values in the long term? Which city should I prioritize? 

2. Any other Denver cities besides these that I should consider, something that might be a better long term investment?

3. Given the appreciation in the housing market, I am too late to enter the Denver housing market? 

Thanks!