Always a fun exercise, even if it's darn well near impossible to actually be correct. If I were Doug Melvin, and if I were being realistic (aka I'd love Mike Lowell, but he's not coming to Milwaukee):
Given that Geoff Jenkins is gone (leaving a hole if the OF), and given that we have an excess of acceptable-to-good SP (Sheets, Gallardo, Villanueva, Suppan, Parra, Bush, Capuano, Vargas), my solution would be one of the following:
1. Sign CF Kenny Lofton, move Ryan Braun to LF, move Bill Hall to 3B. Have Weeks/Lofton OBP and speed combo hitting 1/2 in the order in front of Braun/Fielder/Hart.
2. Trade for a good OBP LF without breaking the bank/dealing much young talent. Austin Kearns (Was) and Josh Willingham (Fla) come to mind. Kearns would serve the dual purpose of being a solid defender on a weak defensive team. Perhaps a package involving Tony Gwynn, SP (Cappy/Bush/Vargas), and a prospect could get it done. Then, move Hall to 3B, Corey Hart to CF, Ryan Braun to RF. To me, this is the preferable option. Go into next year with a lineup of:
1. 2B Rickie Weeks
2. LF Austin Kearns/Josh Willingham
3. RF Ryan Braun
4. 1B Prince Fielder
5. CF Corey Hart
6. 3B Bill Hall
7. SS JJ Hardy
8. C Johnny Estrada
For the pitching, that part's tougher. I think you trade a starter (preferably Vargas if possible), let Cordero and Linebrink walk and reap the 4 early draft picks (kills me to let CoCo walk, but he's gonna get big big dollars).
Sign RP Kerry Wood, RP Ron Mahay. Go into the year with the following staff:
SP Ben Sheets
SP Yovani Gallardo
SP Jeff Suppan
SP Carlos Villanueva
SP Chris Capuano (L)
RP Dave Bush
RP Manny Parra (L)
RP Seth McClung/Matt Wise/any garbage guy
RP Brian Shouse (L)
RP Ron Mahay (L)
RP Derrick Turnbow
CL Kerry Wood
Obviously the bullpen would be very sketchy, and Wood is a perpetual injury risk, but I don't think Cordero and Linebrink will come cheaply. Maybe Linebrink could be retained, I don't know. I don't have a great solution for the bullpen, unless they pull a nice trade (perhaps for a Chad Cordero type).
Anyway, this would be my modest offseason plan. The big picture is to add OBP/defense, add bullpen help, and not shakeup this brilliant young Fielder/Weeks/Hardy/Braun/Hart/Gallardo/Villanueva/Parra nucleus. I also wouldn't make any long term commitments in LF with Matt LaPorta already knocking down the door to the big leagues.