I've had experience with a few Pentax dSLRs and can only recommend them - they have great build quality, ergonomics and features and take great pics.
They're a much smaller company than Canon/Nikon and have more competitive offerings I think.
A nice feature is in-body shake reduction which means whatever lens you attach is stabilised, even old manual focus lenses (you can pick up some really high quality manual focus glass quite cheaply used).
For example you could pick up a fast 50mm manual (or AF) f/1.7 for f/1.4 lens and get the added bonus of shake reduction, a perfect combination for low light situations.
I once picked up a Pentax M 50mm f/1.4 from an op shop for $10! (I was very lucky at that price but just goes to show...

).
Having shake reduction in the body keeps lens design simple and prices lower on new lenses.
I use a Pentax 12-24mm ultra wide lens, normally these lenses don't have inbuilt IS/VR as it isn't needed as much at ultra wide focal lengths, but nevertheless I find situations where it's a useful bonus to have for free that I wouldn't have got elsewhere.
Canon and Nikon do have big lens lineups but I feel there is more than enough choice from Pentax, they have an excellent range of superb small/pancake DA and FA limited lenses, high quality ultra wide, midrange and telephoto zooms and primes.
The 40mm f/2.8 pancake is little more than the thickness of a lens cap

In the much longer fast telephoto segment Pentax don't offer as much, these lenses are >$2k, 5k, 10k, very expensive and I think I'd be safe to say the majority of photographers in the segment wouldn't ever go near anything like these lenses in their photographic journeys.
For the purposes you describe, any dSLR offered today is more than capable of those things, the K-r has a great sensor well suited to low light. I would definitely factor in a tripod to whatever you purchase.
The Pentax kit lens is also a great performer, very sharp when stopped down for landscapes.
I think you'd be happy with the K-r
