This might be the first-ever integration of a Sudoku Puzzle and a Crossword Puzzle.  Have at it. 
E-mail me for the answers...  AThiker@smithville.net
  ( I don't know how to make it printable as is.) 

1

  

2

 

3

 

 

 

 

4

 

 

 

 

 

5

 

 

 

6

7

 

 

 

8

 

 

9

 

10

 

 

 

 

 

11

 

12

 

 

 

 

 

13

 

 

 

14

 

 

 

15

 

 

 

 

16

 

 

 

17

 

 

 

 

18

 

 

 

19

 

 

 

20

 

 

 

 

 

 

 

 

21

 

 

 

Across
 1. Groups of two
4. Chicago’s code
5. Big bird
6. Roan Mt., TN
8. The best pets
10. “For a used car
       call B____”
11. Show-off
13. Low Gap’s highway
15. Praise
16. Ten feet above Abingdon
      Gap Shelter
17. Relieve     
18. AT’s miles
19. Look of contempt
21. South Egremont, MA

Down
1. Group of cards
2. Sexy Thurmond
3. Privies
7. Babylon5 secret code
9. Valley known for Georgia’s
     gold rush
12. Big hill (abbr)
13. High Knob
                                                                                                                                           14. Type of BMW
                                                                                                                                           15. Urine, for one                                                                                                                                                                                                   20. Poorest insulation value