Budapest thermal baths and places suggestions needed

Public transportation seemed very good to me. I think you can buy a day-pass from a vending machine inside the Metro stations or near major tram stops (maybe all stops). If you use individual tickets, hold onto each ticket until you are clear of the station at the end of the trip. There are lots of ticket-checkers.

I'm not clear on whether your city tour is a group thing or you just mean you want to visit those places on your own. They are all over the place, so I am guessing it's a list you've put together yourself. The English-language tours of the Parliament (very expensive for non-EU citizens) normally sell out way in advance, but perhaps some tickets are held back for sale on the day. If you want to take that tour (which I think is the only way you can see the interior), I suggest stopping by first thing on Sunday (it opens at 8 AM) to ask about the possibilities. It will already be closed by the time you get into town on Saturday.

The Opera House is closed for major reconstruction, but there are English-language tours daily at 2PM, 3PM and 4PM. No online booking, and I don't know whether the tours sell out.

From my perspective the major omission from your sightseeing list is the House of Terror, but you have very little time in Budapest, and the best use of it may well be simply to wander around outdoors, enjoying the city.

I really liked the tour of the beautiful Art Nouveau Liszt Ferenc Academy, but it's not cheap at full price, and the English-language tour is offered only at 1:30 PM. I believe that tour does sell out some times, but I think you just have to show up and hope.

If you look back through the Hungary forum, you'll find many posts by James E, who is our expert on Budapest. I know he has made suggestions for one-day itineraries in the past.

We were in Budapest in October of 2014. The Szechenyi Baths were our favorite. Large clean pools, outdoors, and the swirling one was great fun! Easy walk from the metro, and a nice walk through the park on the way back. We used the Szechenyi Furdo metro stop on the way there, and the Hosok Tere metro stop on the way out, which was a great way to visit Heroes' Square. Current prices here: http://www.szechenyibath.hu/prices

Public transportation is convenient. We bought a multi-day pass so we could get off and on as we wanted.

Budapest is one of the most wonderful cities we've visited. We absolutely fell in love. Have fun!

When we first hit any new European city, the first thing we do is take one of the Free Walking Tours where the tour guides work for tips. The guides are generally excellent. Then we'll sign up for their Nightlife/Pub Crawl tour later that night. We just have a great time.
With such a short time in Budapest, I wouldn't waste my time in The Baths. They're actually overrated--and require a shower cap.
Many don't realize what a museum city that Budapest is, with over 200 museums. The House of Terror wasn't anything too special when we visited.
This is our new go to city, and we're going to be back in Budapest the first of April, 2020--our third trip in recent years. It's a city just full of life.

The bath isn’t a bad way to spend an evening. The shower cap isnt required in the main pool, but the others, yes. Some enjoy it a lot, others not so much. I do like them, but if I only had two nights and a day I might do something different. But that doesn’t make it a bad idea.

The one that will be easiest for you will be http://www.szechenyibath.hu/ which will set you back about 6.000 HUF a ticket (with a cabin, a but cheaper if you change in the locker room or go after 7pm) or roughly $20. So, not real cheap. Easy to reach as it’s the next to last stop on the M1 metro.

You didn’t say where you were staying so its hard to suggest a plan for the day.

Using the 2 Tram you can see the:
Market Hall,
Corso (Danube Promenade)
Chain Bridge
Parliament

The 47/49 Tram will get you to the Dohany (Great) Synagogue and the old Jewish Quarter as well as near the end of Andrassy ut.

The M1 which runs under Andrassy ut will get you to the Opera House and the bath house. But then walk back down it, as its worth the walk. The Opera is covered up for renovations but they still run tours most days. Look for the sign in the front.

Gellert Hill, best done with a taxi and a bottle of wine after sunset.

Margaret Island you reach on the 4/6 Tram. Not sure I would spend a lot of time with that. Too much else to see.

Buda you reach, if you are staying in Pest, by crossing the Chain Bridge and taking the funicular up, then walk down. The funicular is 1,000 HUF to go up (about $3.30) or 1.700 HUF round trip.

So, the circle is Andrassy ut on the 47/49 to the Synagogue, then on the 47/49 to the Great Market Hall (ooops, closed on Sunday), then on to river where you get on the 2 Tram to the Chain Bridge where you walk to Buda, then down the hill to the 19/41 Tram which you take to Margit híd where you get the 4/6 Tram to Margaret Island, then back on the same tram to the Pest side of the river where you can get back on the 2 Tram or to Andrassy ut and the M1 Metro. Get a map.

Don’t know anything about boat parties.

And like David, its my go to place. I returned about a week ago and will be back for Christmas.

Thank you. I'm staying near house of terror.

I have change of plans. Planning to see a few places in the evening today. And go to the thermal baths in the morning early tomorrow and then see other places tomorrow. I’m staying near the house of terror. Can you please suggest what places can be seen today evening (starting 5pm) and what can be seen tomorrow?

@James

Unlike David, I found the House of Terror museum fascinating. If you are at all interested in the period of time that Hungary was part of the Soviet Union, it's worth a visit.