Island of the Pirates – with veteran general and xbowmen, no blocking required
(max loss of R is 469R, 87B, 1M)
You’ll need 249 C, 469R, 187 S, 1 M, 66A, 87B (max losses are in parentheses)

C1 100 Deckscrubber, 50 Gunman VS 1S 248C (0 losses)
C2 100 DS, 50 Caltrop VS 41R 130S (41R)
L1 50 Caltrop, 50 Gunman, 100 SR VS 73R 167S (73R)
C3 60KT, 60DS, 60 Caltrop VS 53R 155S (53R)
C4 40 Caltrops, 40 Gunman, 40 SR VS 44R 120S (44R)
L2 2 2nd class, 80 Caltrop, 80 SR VS 50R 165S (50R)
C5 90 Caltrops, 90 SR VS 158R 92S (53R)
Trap 100 Caltrops VS 22R 111S (22R)
C6 100 DS, 30 Caltrop, 40 Gunman VS w1: 36R 2B (36R 2B 1 regular gen)
w2: 1S 249C
C7 100 Caltrops, 70SR VS 48R 187S (48R)
L3 1CC, 10 2nd, 70 Gunman, 100SR VS w1: 45R 85B (45R 85B 1 regular gen)
w2: 6R 1S 177C 66A (6R)

ALTERNATIVE: If you aren't concerned about using fewer than 500R and don't want to lose the bowmen, use the following against L3:
w1: 113R (113R 1G) w2: 6R 1S 177C 66A (6R)

Please be sure to check what remains for enemy troops after the first waves and simulate the second attack to make sure you don't lose more than you wish.