First of all, thanks so much for the kind words, Chica! They are appreciated and helpful. You're right, it's good to know you are not alone.
Looking back at my first "late start" relationship, I've got 5 main challenges besides the overall challenge of actually meeting someone. These aren't solely related to dating but are aspects that I can work to improve in my overall life.
Self Worth
It's first because it's the toughest for me. When you spend years (especially the early years) of your life with a certain mindset, that kind of thinking is hard to change. I never considered myself "worthless" even during my darkest times but my self worth was definitely low. At first, I thought losing the weight would automatically give me all the self worth I would ever need. While it was a big boost, it was only the beginning step. The challenge is overcome that old mindset and see the true miracle of my being.
Self Happiness
Another biggie. I know I shouldn't define my own happiness by how I THINK others see me. I know it, I know it, I know it… but I still allow it to happen sometimes. Other people's words and actions can affect me but they shouldn't define me. It really goes back to my foremost challenge of having a strong center of worth. My ultimate goal with this challenge is to be able, without conscious thought, to give "the full weight" of myself to anyone I meet. If they don't like who I am then it's their problem not mine. I want to have an invincible self happiness resting on an immovable self love.
Self Confidence
I'm seeing a "self" theme developing here. I think a lot of confidence will come by working on my first two challenges but confidence in a relationship will only come via experience. Before my first one, how I'd manage in a relationship was a big unknown. Now, I know I can do well, not perfect, but still ok - my irrational fear of being a complete failure? OVERCOME!

Sure, I'll have missteps and make mistakes but they will help me learn. I thankful for all that I learned from my first relationship and for the boost in self confidence that it gave me.
Body Image
If only mirrors didn't exist <sigh>

… NO, that wouldn't solve anything. I know am I fit and healthy but why do I only see my body as a deflated balloon of my past mistakes? I have corrected those mistakes and they shouldn't cause me shame or embarrassment. Yet, too many times, I let my body image affect all three of my first challenges. I just find all the loose skin to be a constant discouragement. I've admitted to myself that plastic surgery might be the only solution to totally overcoming this hang up.
Communication
Maybe a challenge, plain and simple, for EVERY guy but I still find it frustrating. I'm afraid of saying something wrong or stupid while trying to express how I feel. So, I end up not saying anything. I pick up a weird vibe from her. I don't mention it because I don't want to sound like some lovesick teenager afraid that his girlfriend doesn't like him anymore. I want to express my own relationship insecurities but don't know how to even bring it up. Looking back, I know all these communication failures on my part hurt the relationship. The challenge is to become comfortable with this sort of "deep" communication in the future.
I'd really love some feedback on all of these including anything you think I've missed.
Mark