Hey jgyblouieve or whatever the heck it is,
Congratulations. I've had my 2305 for about 2 years now, bought new. I have a boatload of attachments for it, including the 200CX BL, 260 BH, 54" MMM w/ independent lift and the bypass valve, and the ballast box. I live in Ma and I have a 300 ft paved driveway, steeply sloped.
-The bypass valve is useless unless you plan to keep the bucket on at the same time as the MMM. Don't bother with it, you'll rarely be in this situation if you care about your stuff. When I'm bucketing, the last thing I want to worry about is what might be hitting the mower deck. it only takes 5 minutes to remove it.
-I wouldn't want to use this tractor to mow if it didn't' have the independent lift. Life's too short. Without it, you have to use the 3PH lever to raise and lower the deck and the lift arms will go up and down too. Yes, the lock that keeps the deck raised isn't perfect. The way it works is there is a notched cam that keeps the deck raised in varying amounts, depending on the position of the adjustment nob between your feet. In my opinion, the cam lobe that keeps the deck raised all the way could be 1/4" taller and then nobody would complain, including me. I'm thinking of welding a nut or something on it to get a bit more height but it's just a minor aggravation, really.
-You can raise/lower the bucket while curling at the same time. You just have to get used to it and find the sweet spot. The same goes for the backhoe.
-I used to use my ballast box while snowblowing, but I don't bother anymore. No rear weight. I go commando. In fact, I take off the 3PH lift arms too so I can back right up against stuff and also not worry about hitting things as much. I'm so used to snowblowing now that I can be reversing at full speed, spin the wheel, bring the front end around while dropping the blower, and head on back in the opposite direction. Starsky and Hutch like. I don't use chains because I have to look at the driveway all summer but I do have the R4 tires. I wouldn't mind having loaded tires but, like you, I have to mow grass with it so, no-can-do. Maybe I'll pick up some wheel weights if I find a couple hundred in someone's coat at a restaurant.
-Oh, one important thing. Whenever I'm not on pavement, I'm usually in 4WD. Whenever I'm on pavement, I'm NOT in 4WD. I freewheeled down a grass hill one day early on because I was in 2WD with the bucket on the front with just a "tad" of dirt in it and no weight on the rear. I barely managed to get cross camber and slowed the tractor down. That moment is always in my otherwise empty skull when I'm on this machine. I've also almost gone over a couple of other times due to my very hilly land. (Why did I buy THIS house?!!!)
-Another thing you'll hear all over the place is to watch out for the hydraulic filter and tranny cooling fan underneath. Don't go doing anything stupid like driving over a pile of brush.
Get yourself a lube gun and use the **** thing once in a while. Good luck.