Ok can I presume that my PrC gives the spear/lance weapon group, and X others?
No, you may not presume that. As a paladin you get basic + 3 weapon groups. That is all. A prestige class doesn't grant any weapon groups unless it would otherwise be an improvement over what your character already knows.
What group does a shield bash fall into?
Weapon Group (Shield Bash). It's not on the list, but it's what I've used before for people wanting to use a shield as a weapon without the proficiency penalty.
Can my contacts be a caravan Leader (Informative) that moves on a regular route between a couple of the major cities, and representitive of the wizard's guild (Skilled)?
Sure, I'll figure something out along those lines.
Still haven't found a good map of the area to choose where my contacts are from.
Try these. Few maps give the detail of showing communities as small as a village.
Map of Greyhawk Flanaess
ghmaps - maps (specifically 59 and 60)
There used to be tons of TSR downloads at sites like the ENWorld store and DriveThruRPG but I can't find any for the life of me.
Would a heavy adamntine shield give DR X/- the way adamantine armor does?
Only adamantine armor grants DR. You can purchase adamantine shields for the same price as an adamantine weapon.
Ok I need to break this down specifically. So since my adamantine lance is going to be large sized, its base dmg is 2d6+1 (the 2d6+1d6 from vicious doesn't count toward damaging the lance and gets added after all the multipliers). str adds to this dmg for the purpose of damaging the weapon i gather from the above statements. That brings the base dmg up to 2d6+10 (I'm weilding it 2 handed) on a charge this goes up to 6d6+30 (8d6+40 with Rhino's Rush). So every charge is going to damage the lance regardless of its composition, but the adamantine raises hardness to 22 and hp to 90? (40 for Adm X2 for large size +10 for the +1?) which should let the normal attacks leave it undamaged right? (since the dmg for a normal attack is 12-22.)
You can't make a lance from adamantine. As per the DMG "Only weapons, armor, and shields normally made of metal can be fashioned from adamantine." A lance is made from wood. If you somehow ingratiate yourself to a high-level druid, I might allow you to purchase an ironwood spell.
I'm guessing that you wield the lance two-handed because you have the animated shield.
Would the Innattentive flaw work with my character? I'm thinking about the Shorten Grip feat (DR331 pg28) which allows me to shorten the reach of a reach weapon for -2 to hit.
The way your character is designed, you won't be making any important Spot or Listen checks anyway. I would hardly call that a flaw.