[Kyle_Olsen]

Try getting the nearest vehicle ID, I'll find you the stock...

pawn Code:

stock GetNearestVehicle(playerid, Float:dis)
{
    new Float:X, Float:Y, Float:Z;
    if(GetPlayerPos(playerid, X, Y, Z))
    {
        new vehicleid = INVALID_VEHICLE_ID;
        for(new v, Float:temp, Float:VX, Float:VY, Float:VZ; v != MAX_VEHICLES; v++)
        {
            if(GetVehiclePos(v, VX, VY, VZ))
            {
                VX -= X, VY -= Y, VZ -= Z;
                temp = VX * VX + VY * VY + VZ * VZ;
                if(temp < dis) dis = temp, vehicleid = v;
            }
        }
        dis = floatpower(dis, 0.5);
        return vehicleid;
    }
    return INVALID_VEHICLE_ID;
}

Paste that on the bottom of your code... Then change the code to

pawn Code:

if ( (newkeys & KEY_SECONDARY_ATTACK) && IsPlayerInAnyVehicle(playerid) )
    {
        new nearest = GetNearestVehicle(playerid, 5.0);
        PutPlayerInVehicle(playerid, nearest, GetPlayerSeat(playerid));
    }

The seat however, I don't know how to get out of it...