I pull over to the far right of the lane, so a car can pull up and trigger the sensor.
Ok, pretty much what I do, too. I hate being first, especially when I am in the left-turn lane. 
Then I pull up as far as I can. There is usually enough room between the white line and the crosswalk for me, and thus I am not blocking either.
There is a problem. Sidewalks are for pedestrians, and in many locations, it’s not legal to ride on the sidewalks. Even at a slow pace on a bike, you’re much faster than a pedestrian, and much less responsive to changes in direction. Anaamika also raises good points on the issues involved with vehicles crossing the sidewalk at driveway openings. I’ve caused more than a few problems in my time as a kid with this exact problem.
Bikes are vehicles, stay on the roadway, or find a non-road bike path. Stay to the right of the roadway, with the direction of motor vehicle traffic. (just like a car). Pedestrians should walk on the left towards oncoming traffic.
Years ago, I bought a rigid frame mountain bike, and in retrospect, I really wish I had bought a road bike. I’m far more likely to ride on the roads, as off-road in New Hampshire generally involves thin trails, and steep hills, neither of which I like. The recreational trails are generally filled with loud ATVs/Dirt Bikes, which spoil the “off road” experience with noise, and they tend to churn up the roadway, making it unpleasant to bike on. Even with a semi-slick tire, there is considerable friction on the pavement for my mountain bike, and the high gear isn’t nearly high enough for my taste.
Think about where you want to ride, and why, then visit a few bike stores to get their opinion, and see what the options are.
If you are interested in getting better at riding in traffic, I HIGHLY recommend this book: http://www.amazon.com/Art-Cycling-Bicycling-21st-Century-America/dp/0762743166/ref=sr_1_1?ie=UTF8&s=books&qid=1270765940&sr=8-1