Well, it depends really... you want a front end loader I saw, that is going to be a HUGE pain in the butt for mowing. Your screen name leads me to believe you are in the flat lands haha (I should be a detective huh?), so you may not have the same challenges that I face living in the mountains... however, there are things that a larger tractor will do that a smaller one absolutely will not... With small tractors 4x4 is really nice, for me I don't even need 4x4 on my larger massey, I mentioned the little kubota without a differential lock will sometimes take a slide down a hill while I'm mowing though... I'd say a Diff lock would be on the top of my list when I replace it. The other thing to consider is that while you would double your maintenance costs by having two tractors, if you are going to try farming for a living and a tractor is essential to your plan, having a second tractor is really nice... If I were you I would seriously consider a small tractor in really good condition with no loader and at least a 5 ft. 3 point finish mower for my "lawn mower", trust me, it'll save you money if you can get a good deal on it... I was spending a TON on fuel for just mowing our grass and it sounds like we have about the same amount to mow. My little kubota is a 2 cylinder 18 h.p. and is quite surprising in what it will do..
your specific question of maneuverability, I would assume a belly mower would be more maneuverable than a 3 point, my stepfather has a belly mower for his tractor I referenced in my earlier comment and he curses it constantly, it's a bit of a pain to remove and he removes it quite often... Oh, and, if you go with a 3 point mower, either buy a rear discharge or convert the side discharge to rear (I did this and it worked just fine)... With a side discharge, if you let the grass get away from you, you will lay out BIG rows of grass (kinda like when they prepare hay for bailing) and you will constantly fight and choke on those over and over again (unles you actually have a hay bailer and can bail it!)... Last year it rained so much that I couldn't mow because of the mud as often as I would have liked and had to constantly fight the big rows of clippings I left, so I cut the back off of my mower, removed the little circular blade chutes (if you see under one, you'll see what I mean) and welded part of the back over the side discharge hole... works perfectly! Side discharge mowers are MUCH cheaper than rear discharge, but it works just fine doing what I did... Now when I mow, it scatters the clippings behind me in a 5-7 ft. area and they don't pile up, plus I can mow a little bit taller/wetter grass without slipping the belts on the mower....
Ultimately, your particular piece of land will determine what you need to do, for us though I found having a big tractor for big work (such as plowing/tilling) and having the small tractor for mainly grass mowing and light duty bush hogging has been the way to go... I recently got another 2 wheeled tractor (after selling the bcs last year) because I put my big tractor into a place that I shouldn't have and got a flat... the gravely cost less than the tire I busted, so I figure (eek) the gravely can be a sacrificial thing, I'll take it as easy as I can on it, but for the price, I'd rather lose it than put another tire on my massey... Your land may be such that you don't need a 2 wheeled tractor at all, but I have creek banks to clean up alongside and the beavers like to chew stumps to little tire spears out there haha...
so, In my opinion, yeah I think it would be a mistake to get one tractor to do it all... I think if you spend wisely and wait for the right deal you can come out like I did with some decent cheap machines, I would get a nicer small tractor than a big tractor though, you'll be using it quite a bit more if you're mowing, and at least around here, I find big old farm tractors all the time with loaders even in the 2,000-3,500 range, just check them out very well, tires are expensive and if they need rims too (from putting calcium in the tubes) then you're looking at around 2 grand just for tires/rims and remember about leaks, most old used tractors will leak a little but if they're leaking alot that adds up from all that money pouring out on the ground!
If you're doing this on a serious budget like us, paying a shop to work on a tractor is out of the question, most places around here want $160-$180 per hour to work on your machine, I'm a pretty good mechanic but you don't really have to be as long as you don't get too new/fancy with your tractors, a good real factory service manual (you're gonna pay 80 bucks or more for one) and even a little bit of mechanical skill (plus awesome forum help like here) will carry you a long way.
I hope that helped some, I wish I had learned these things at the first, would have saved me alot of hassels for sure! Grass mowing is probably my number one job here, that and weeding our blueberry orchard (organic so I can't spray)... With the ground you described, depending on your location, you may be in the same situation, if so, then a nice small fuel efficient diesel machine will be great for your chores...
On a side note, my massey 65 diesel seems to be a VERY fuel efficient machine for its size, most guys who own one agree that theirs just sips fuel also... nothing iike my kubota, but the few times I have had to use the massey with the finish mower, I was impressed... The 18 h.p. kubota will go as fast as the finish mower can mow the grass without choking the engine out so for us, that critter is perfect... I can mow in Hi-2 (or 6th gear) and move pretty darn quick... Not as fast as some of the fancy zero turn mowers I've seen, but still as quick as I need to...
*edited*
I wanted to add, I start and use my Massey every few weeks (unless it's during plowing season like now), my kubota gets used every couple of days at least, that's why I said to get a little nicer small one as at least for me, I use it quite a bit more... I could put a loader on the massey and it would be a little bit of a pain to use it, but it would be fine, If i put a loader on the kubota I know I would curse it all the time for being in the way... Also, while I LOVE diesel, the massey could honestly be a gasoline tractor and be fine since I don't use it often enough for fuel to be a huge issue, so if you're getting a couple of tractors, the big one for the heavy work don't pass on a great deal for a gasoline one... the plus side is, if it gets really cold where you live, that one will start in the cold much easier!