More places

Here are a few more places not yet included, I have visited a while ago, but as yet not added to the blog...one day

30 mins or less
Ampthill Park - just open parkland hilly in places with view over towards Marston

Caldecotte Lake MK
Coopers Hill - Ampthill's very own heathland
Bedford Embankment - pretty walk along the river lunch/brunch tea at https://thelongholme.com/

Bedford River Trips https://www.bmkwaterway.org/johnbunyanboat/
Cardington Sheds - you can drive past them and then drive through to Old Warden and tea at Southilll Tea rooms

Charles Wells brewery https://www.brewpoint.co.uk/ 
Dunstable Downs - hills, great for kite flying and watching gliders
Harrold Odell Country Park https://hocp.co.uk/
Marston Vale Country Park/Stewartby Lake (pay for parking now)
Maulden Wood
Priory Country Park

Ridgmont Tea Rooms (in the old railway station, and if lucky you can see the small station museum/exhibit)
Whipsnade Zoo
Whipsnade Tree Cathedral
Woburn Gardens (closed till 2024) have visited in the past

1 hour or less
Anglesey Abbey (NT)
Cambridge
Cambridge Botanical Gardens
Capel Manor Gardens
DOCWRA Garden near Royston

Dunstable Downs (tea rooms at top by NT)
Duxford Imperial War Museum
Frederick Gibberds Garden - Harlow, quirky gardens with a lot of individual pieces of statuary collected by Sir Frederick Gibberd, tea rooms.

Godmanchester
Grafham Water
Linton Zoo

Silverstone Museum https://www.silverstonemuseum.co.uk/
Wimpole Hall (NT)

Just over an hour:
Capel Manor gardens
Waddesdon - (NT & HHA)

If you are looking for somewhere to stay I can recommend Sunnyside lodges small self contained self catering units.

and here are even more places not visited but have seen mention of them:

Ashwell Spring
Baulk Wood
Cainhoe Castle
De Grey Mausoleum
Henlow Common
Ickwell Green
Keeper's Cottage
Langford Meadow
Moot Hall
Norton Common
Old Road Meadow
Queen Anne's Summer House
Radwell Meadows
Sandy Heath Transmitter
Shepreth Wildlife Park
St Neots River Walk
Standalone Farm
Stanford Wood
Thurleigh Farm
Tunnel Nature Reserve
Warren Wood