Camden is a couple of stops from Euston. Not my cup of tea round there but plenty love it.
Personally if you want to do some walking, which at the moment may be preferable to being sat on the tube then for me the best place to stay would be somewhere where you can walk to all of the places below.
London is surprisingly walkable and I would avoid the tube if at all possible. Newbies to London sometimes get on a tube at one stop and then off at the next when it is literally 200 yards between them.
Westminster for Houses of Parliament/Big Ben/Westminster Abbey and St James park (Buckingham palace is walkable from there as is Hyde Park). You can catch the hop on/hop off boat from there too. Takes you right up to Tower Bridge and beyond.
Over the river at Westminster Bridge is the London Eye, South Bank Centre and you can walk right up to Tower Bridge from there passing the Globe Theatre and Borough Market (My favourite food place in London). It’s a lovely walk on a pleasant day.
Leicester Square/Piccadilly Circus and Convent Garden - Touristy but doubt there will be many overseas visitors so should be quiet. If you have never been to London then good for statues/shopping etc. Regent Street is off there and Carnaby Street hidden away behind it.
Soho is where all the Theatres (mostly shut I guess) are but from what I have seen there are plenty of people still eating out and drinking around there, particularly at the weekend. It is usually a place full of life but not sure it will be as vibrant currently.
The British Museum is worth a visit and like all museums in London is free. Not sure what the rules will be there though currently.
You haven’t said which weekend but the Premier Inn Leicester Square is right in the middle of it all and is an absolute steal at £68 a night weekend of 23/10! Usually sold out that one and often 2/3 times that price!