Im am playing in Portland, and wondering what kind of players would work well in that park. It is a (-4,-3,-4,-2,-2) park and the team i inherited has Power guys, but guys that would normally hit 30+ are hitting like 20-23 HRs. What kind of pitchers and fielders work well in these types of ballparks?

Thats one of those things you have to figure out on your own...
The singles factor is the only one that effects batting average. The -4 rating there means BA will be low. The other ratings display the odds that a given hit will be for ectra bases. Take that for what it worth...

Building HBD teams doesn't require a degree.   Obviously, as you can tell, power is diminished.  So, since you're not getting 3 runs homers, you have to do something else.   In fact, all hitting is diminished.   What isn't affected?  Speed and eye.   Walk and steal a base.   That's not to say you shouldn't have power hitters as you'll be playing in other parks but speed/eye will still be useful in those parks. 

As for pitching/fielding, nothing really changes unless you're a guy who frets over GB/velocity.   Those are less of a factor due to the park.   Good fielding is good fielding in all parks.

Good teams win, regardless of park.

The rest is cosmetic.

FWIW, I've led the league in HRs playing in San Diego, which isn't all that different from Portland.

What I've seen too many people do is get too focused on one aspect of their team.  So they load up on as many power guys as they can, but many of them that you're able to acquire easily strikeout too much.

Others may focus solely on speed and defense, but fail to score enough to win any games.

Others may focus completely on pitching, but fail to score enough here too.

You need guys that get on (and perhaps steal bases to get over), you need guys to drive them in, you need defense that won't hurt more than they can make up for in offense.  You also need solid pitching that can keep pace with your hitting.  Obviously there's give and take on all of these, but don't get so focused on one type of player that you dismiss other useful players.

My two cents; all a ball park does is allow you to get away with a certain type of player when filling out roster spots 21ish to 25.

Good players are good players anywhere. A pitchers park will allow you to get away with a certain type of pitcher that would be high 4 ERA in a neutral park and a certian type of defensive fielder with a weaker bat. A hitters park will allow you to get away with certain types of batters, which I haven't figured out yet thus I stay away from it.

I would think that you would take the contrarian view of players.  If your in a park like portland and you are deciding between 2 guys, one leaning to off the other to def, I would take the off guy.  For 81 games your park will help him, and his off might make up for any def liabilities on the road.  Conversely, if your in say hartford, I would focus more on guys who have slightly better D, for the opposit reason.  You might have an offensive juggernaught at home, but can't field and catch away.