I spent 2 months in Meetirigala (Nissarana Vanaya), and one month at Ven. Pemasiri's Kanduboda (there's two, one old and one new)
I eventually got fed up with Meetirigala and the fact I was not only discouraged from reading - Nyanavira in particular, but the only English speaker for much of my stay was the abbot and Dhamma teacher, and he wasn't impressed by my interest in Nyanavira's writings and so there was a fundamental irreconcilable difference between us. I was also discouraged from writing to my family, that - Like my attempt to learn Singhalese was discouraged because the Venerable sir felt that it would detract from my meditation. I'm not passing judgement on that, just stating the fact.
There were many good points however, for an independent person who is interested in a Burmese style of meditation. It was (at the time of my visit) very good for solitude, talking was more or less discouraged, but not enforced. So if you wanted to discuss Dhamma with a fellow English speaker (if there are any staying there) you can. The food by Sri Lankan standards is pretty good, lots of fruit. As an eight preceptor you will go down the stairs and do some begging in a staged almsround type thing, there are lots of different spicy vegetable curries, red and white rice etc, there is usually dessert or candies at lunch - Lots of curd. Really good milk tea in the mornings - Still trying to learn how they made it there - So if you go there can you ask them for me and report back? I have a feeling it includes some kind of malt... Strange request, I know.
The kuti I stayed in was pretty spartan, the bed kept collapsing so eventually I just popped the mattress on the floor (it was the only innersprung matress I slept on the whole time I was in Sri Lanka, so if you find one, cherish it. The area is a rainforest, and there is no electricity in the kutis so you will need to get matches from the supply monk to light your candles/lamps at night, I would recommend buying a lighter in Colombo though as it's easier in the long run as matches go bad in the humid environs quite quickly and need to be stored in a glass jar. There were issues I had with monkeys, dogs, snakes, scorpions, spiders, ants, leeches, cockroaches and mosquitos, if you wish I can give you an interesting story about each one, but the fauna certainly wasn't a deal breaker, just something one needs to adjust to. The monks and on site lay attendees do not by and large speak any English, which has both positives and negatives. Overall actually, the monastery has a lot of positives and it's fair share of negatives - I would definately say one needs to be very independent and used to solitude. I wasn't, I was used to the style of the Ajahn Chah Western Sangha monasteries where the focus is definately on community living, and so the adjustment proved too much for me. But I really do feel that there are certain types of people that would find Meetirigala perfect.
On a more general note:
You will need an umbrella, rain can come on very very quickly and disappear just as fast, but when it rains in Lanka, it pours! Also, when you go to Meetirigala you will need to bring white cloths, I would recommend getting some white sarongs at a shop in Colombo, as they're much more comfortable in the humid hot weather than pants.
As far as getting around the country goes, some basic Sinhala will come in handy in general - Basic travel stuff like 'I want to go to X'. You're easiest method for short distances is tuk tuks, Buses are mostly all written in Sinhalese script so you will need to ask English speakers for what bus to catch, if you're lucky they may have a subtext in English script.
I can give you some info on Kanduboda if it's indeed Ven. Pemasiri's one and not the original Kanduboda.
Hope that helps for a starts
"For a disciple who has conviction in the Teacher's message & lives to penetrate it, what accords with the Dhamma is this:
'The Blessed One is the Teacher, I am a disciple. He is the one who knows, not I
." - MN. 70 Kitagiri Sutta