My trail shoes generally get hosed down whilst still on my feet if they are bad (at the same time as hosing the dogs down!) then I just stick them infront of the AGA and they'll be dry by the next day. I did buy black ones though so don't worry about it much - actually find my road shoes worse as they are white and the muck of the roads is horrible. Tend not to bother cleaning them at all, just stick them infront of the aga to dry and then put them on again
I have two cocker spaniels who run with me every time I go. I'm currently running up to 8-9 miles and they happily do this (although I'm running at about 9 min miles). This amount of running does not exhaust them, they will still go mad round the garden when we get back!
I do run with them on leads, but they are not allowed to pull - they have to run to heel. Yes, having them on lead does mean that I have to allow them the odd wee stop - but they aren't allowed to just stop whenever, its when I say so.
Mine are nearly 6 years and 2.5 years old and both have run regularly with me for over a year. They are also brilliant family pets. I will point out that they are Working Cocker Spaniels, not the show type, therefore they are bred to run all day flushing out game birds.
With any breed of dog, you need to do your research. If it is going to be a family pet, then temperment has to be your first priority, does it require alot of grooming? (my spaniels need a fair bit). With any breed, you need to spend the time training them (my youngest has not had enough training, hence can't be allowed off lead in open areas - my fault, not his) and the whole family need to agree on what is and isn't acceptable behaviour. Find a puppy obediance class and take them as soon as you possibly can.
MR2 - Yes they do I'm a biker and we all nod as we pass and I have been known to stop to make sure bikes pulled up at the side of the road OK. I've made loads of new friends in the past 18 months since I've had a bike.
Presuming it depends on the environment you are running in. As has been said, running in a city people tend to ignore each other (not just runners but everyone!). I run on country lanes and everyone tends to speak or wave. That said, sometimes it can be half an hour and I haven't seen anyone walking / running / cycling / driving!
Motorbikers tend to all nod at each other too - can get a bit repetitive when there are a dozen bikes going past you