There are some £24.50 Haddenham to Nottingham Advances (via London). Combine with a Nottingham-Boston Advance at £10 or £8 or £6 depending on journey time.
Or there are some £5.50 Haddenham to Birmingham (Moor St or Snow Hill) Advances e.g. on the 0738. Combine with an £11.80 Birmingham New St-Nottingham Advance, and a Nottingham-Boston Advance as above. Certainly under £30.
Or £3.40 on the train to Bicester North or Bicester Village, £11 on the X5 bus from Bicester to St Neots, £4.90 single from St Neots to Peterborough, then either: a £16.90 single from Peterborough to Boston; or £4.50 on the 37 bus from Peterborough to Spalding, plus whatever it costs to get from Spalding to Boston on the B13 bus. Most likely under £30 if you use buses between Peterborough and Boston.
NB There are rail replacement buses between Peterborough, Grantham and Newark on the 25th, and no direct trains between Grantham and Sleaford that day, so travel via London & Grantham may not be the best option on this particular Saturday.
