There is 2.2yrs between my DS & DD, and I have to say although it was chaos at first it wasn't as bad as I feared!
DP couldn't take paternity leave and I'd had a c-section due to PE with DD so we enlisted the help of MIL, who would move it for 3 days at a time to help with the cooking, house maintenance and letting my have time with DS whenever DD was sleeping. For the first month she was a godsend, after that I was back on my feet, DD was going a wee bit longer between feeds & I could drive- suddenly life got a bit easier and more enjoyable again!!
Like others have said it's critical that you try to find time to spend with your eldest as they will need that. At least newborns sleep a lot even if only for short periods so you can do play-doh, painting, reading, singing etc. with your eldest while the LO sleeps without having to leave the house. During the mammoth feeding sessions that DD had we'd resort to DVDs quite a bit to keep DS from marauding around the house causing havoc (he was at that age!) but as he got used to me breastfeeding DD he learnt to play around us- I'd always sit on the sofa to feed DD so DS could sit next to us, often we'd read stories or play little games (the advantage of breastfeeding is having one hand spare!). I very much involved DS with DD's care- he'd help change nappies (handing me cotton wool etc.), bath her etc. To this day he loves helping out and has never yet been violent/aggressive towards her, which was my greatest fear.
DD is now 7 months old and DS 2.10yrs and life has got into a good routine (DD sleeps through luckily, so we have evenings back after they both go to bed at around 7.30pm ), although we are pretty flexible too...
Getting out was tough at first, we have a dog that needs lots of walking and DS needs these too or else will wreck the house (bless) so I found a sling for the baby best- DS is a great walker (I trained him during last months of pregnancy by walking for 30 miins each day with the dog, which worked well!!) so we rarely use a pushchair (only when going into town for shopping). Now DD is in a backpack which is even more comfortable and still leaves my hands free to keep a tight hold of DS' hand!
There are certainly many days where it seems like utter chaos, or takes HOURS to get out of the house (still doing 2 lots of nappies etc.)- and it's taken me a while to not worry about how messy the house is! But watching the two of them together makes it so worth while- DD just adores DS, and he's pretty enamoured with her too. I know they'll fight at times (already she's after all his cars etc. so the word "share" is being used A LOT!) but hopefully their closeness will last.
Good Luck!! And enlist the help of as many people as possible in the first couple of months!