Currently I live in a townhouse - which has a TEENY yard (fenced in/6ft). I have no problem getting up early to walk the pup and again when I come home. There are no dog parks in my area, so what other ways/places do you let your pup run loose in? Or is a 2x daily walk/jog enough during the week? The weekends are a different story b/c I have all the time in the world.

I think you'll have to carefully research your own neighbourhood, maybe ask other local dog-owners where they go. I also live in a townhouse with a teeny yard but I have a 300 acre park about 400 yards from my front door so it's easy for me.

Regarding the work day - until I get that perfect job that lets me work from home, what do you do with your dobe during the day? Crate it? Let it run loose? Only allow a small portion of the house to use? Doggie daycare?

You'll probably get 10 different answers to this question! Letting a dog have access to the whole house is asking for trouble though, unless you are absolutely certain of your dog - crating is one solution, so too is a puppy-proof room or area. Baby-gates are your friend A fully day is much too long to crate a dog though - I'd look into doggy daycare or consider hiring a dog-walker/dog-sitter.

Maybe a silly question, but what are some ways to show I'm the "alpha dog" so the newly adopted does not think he owns the pack?

Try not to think in those terms. You don't need to 'show'; you just need to 'be'. If you are a normally assertive person, consistent with boundaries and rules, and give your Dobe sufficient exercise and training then you'll just be "Alpha" by default.

Other than age, is there much difference in adopting a 1 year old versus a 4 year old dobe?

Individual dogs vary a lot. A 1 year old will likely be much more of a handful but over time you can shape it more. A 4 year old will likely be calmer but less malleable. But it really does depend on the individual dog and its history.

 

{Maybe a silly question, but what are some ways to show I'm the "alpha dog" so the newly adopted does not think he owns the pack?}

Please get this notion out of your head. Be calm and confident in all training and you should not have any problems.
{On average (if you have a perfectly healthy dog, other than heartworm prev), how much should I expect to dish out for bills in a year? Including food/toys/crate/bed/vet, etc?}

The initial expenditure is the most then it settles down unless you have an emergency so food, and vet check should be in the realm of $600 to 800 a year roughly

{Is PetSmart a good place to get obedience classes? Why or why not?}

Only for socialization

I have not been impressed with their training classes - lots of book learning little actual dog knowledge on the average.

{Other than age, is there much difference in adopting a 1 year old versus a 4 year old dobe? }

A one year old is probably easier to train and hopefully with less issues. A one year old is still a puppy so can be destructive if left to their own devices will need more training. A 4 year old is more settled, should be good on house training - could have more issues that would require more training.

{Since some dobes that come into rescue may have no history/background, what sorts of questions should I be asking? Other than temperament? Do rescues have all the health checks done by the vet?}

I would want to know everything that they know - why was the dog turned in? Do they know if the dog was abused or neglected in any way??? Has the dog shown any dog aggression, human aggression, food aggression??? I think rescues have the dog check for standard things - it will not have the major testing done, OFA, Thyroid (probably unless they think that there is a problem with it) , cardio