I've stayed at the Newport Beach twice in just over a year--but only in the off season (too expensive for me in the summer!)
It has definitely been renovated. There are 2 buildings, the new one with all suites and the older one with renovated rooms, but of dramatically varying sizes. In both buildings you could have ocean views, but you wouldn't see any of the mansions. (There's no place in Newport where you'd have those views). They seem to charge extra ($20?) for rooms with a view , at least in the main building, though I have been upgraded (without asking) when the hotel isn't busy.

The Courtyard etc are a couple of miles out of town, Not really far, but I liked waking up to the ocean instead of a strip mall

I can't imagine many crowds,but I don't know how popular the Easter events are. There are always tour groups at the Breakers which is one of only 3 mansions open year round. Looks like a couple more are open when you plan to visit.
Weather? unless it rains a lot, it should be nice.It seems warmer on the coast that it might inland pr at higher elevations

Really good tip: sign up for a text messages on your cell phone from the Newport Restoration society. I see the number to send to is 82672 (I'm looking on my phone's inbox) but I don't remember what you have to text them. I think it;s just NEWPORT, if you want to try, If I can find it on the Newport website again, I'll post it here.)
They don't tell you this, but I have always gotten a code to get a 5 mansion pass at a two-for-one rate. (you just show your phone the admission desk)
Although I used this in the winter when most mansions were closed, the 2 passes cost less that 2 admissions just to the Breakers! The passes don't expire, so you can you some and then come back another trip, give it to someone else, etc

If you get your fill of mansions, drive over to Little Compton. It is just across an estuary but a world away. You can see Newport, but you are in a very rural world of lush farms and vineyards. It helps if you have a GPS since the roads are not well-marked, probably deliberately.

Great suggestion, Ackislander. It's true that the roads into and out of Little Compton are challenging (even though I learned to drive on them!). happytraveler, if you're interested in this suggestion, a little closer and more straightforward option would be the adjacent town of Tiverton, with its Tiverton Four Corners shops and restaurants (google it for more info).

I can't imagine many crowds in Newport in April; I think janie has given you some great advice.

As long as the weather's not too blustery, definitely try to do at least part of the Cliff Walk: gorgeous ocean views on one side, the backs of mansions - museums and functioning residences alike - on the other...

Here's a thread on Newport restaurants. I contributed, along with several other folks:

http://www.fodors.com/community/united-states/dining-in-newport-ri.cfm

my grandmother was one of the irish immigrants that met at the 40 steps. love walking the full length of the Cliff walk, but it does have some dicey areas so proper footwear is essential.

http://www.cliffwalk.com/sect2.htm

we often park on Narragansett and walk the cliff walk and then take in the glorious old treed walking our way back up Bellevue.

If you're looking for a clamshack experience we have had wonderful and horrible food at
Flo's. I suggest ordering one platter to share and taking it from there.

It's only the latter section of the Cliff Walk that's "dicey". Kea, I see the URL you provided is for "sect2", but I wanted to make that clear for anyone who wants to walk just a bit of it! It's easy enough to cut back up to Bellvue and walk along the fronts of the mansions once you've had your fill of the brisk salt air.

Forget the Marriott and Hampton Inn. They're fine hotels but they're actually in Middletown which is not as nice as Newport and you would need a car to get to anywhere where you want to go. The crowds shouldn't be bad...probably enough to make it fun but not enough to be crazy. The weather could go either way since it is New England but for the most part it should be getting warm (mid 60's/70's) around that time. Definitely do Cliffwalk and Bellevue. Also, if you're looking for some funky shops and restaurants head down to Broadway...my fave's are Salvation Cafe (the teens will love it-fun and great/inventive food and drinks), Fifth Element, and POP is a cool place for adult bevs. Broadway is off the tourist path, more a locals hang-out. Also, take time to walk the side streets off of Upper Thames and Bellevue- great houses and little hidden shops. If you do have a car then drive Ocean Drive all the way around - it skirts the ocean and the views and houses are amazing. Have fun!