well, im finally moving over all my important pokemon from pearl to plat, mostly for the better battle frontier. however, this will lower their happiness to base, which actually matters for my return users (slaking and staraptor). is there a better way to get them to max happiness than biking the breeding route? they're both already lv 50-ish, so it'de take a while to level them.
Sorry, I misspoke. You just want happiness, not level-up, so you don't need the daycare. All you need is the Ironworks.
Take your Pokemon to the Fuego Ironworks and use little plastic clamps (from the hardware store for about $1 each) to hold the down button and the B-button to make your guy run (not walk) onto an arrow tile all night long. I like the tile that throws you upward for 13 steps. Plug in the charger, go to bed, level up in the morning. Done.
Some people use weights instead of clamps, but the clamps are more secure. --- I hereby pledge not to buy any new games for myself until HG and SS are released. Number of people who have joined me in this pledge: 2
I usually attach a Soothe Bell to the pokemon whose happiness I'm working on (I'll use my old Golbat as an example), then I go to the trade boards and find out what pokemon people want bred (I stopped trading for new pokemon just a couple of days ago, but I used to stay on the Trade Board for hours at a time). While I get the Feebas (it was in demand at the time) bred and occassionally hatched, I kept Golbat in my team. My team was Infernape (my starter), Golbat (obviously), and whatever eggs I was bringing to an almost ready to hatch status. I would keep breeding whatever was requested at the time (Clamperl, Dratini, starters, whatever was in demand) until I had biked enough to bring my Golbat to a maxed out happiness status. After it was ready, I went into the tall grass and got into a battle (and lucky me, I had a battle with a Chansey). After the battle my Golbat was levelled up to 23 and evolved into a Crobat.
In the end, I had my poison and flying pokemon of choice, plus 2 dozen pokemon being asked for on the trading board. With the technique I use, everybody wins.