Advice on good running and family friendly location for week break at Xmas

Am wanting to go away for a week at Xmas/New year. Will be gearing up for marathon training so quite important wherever we go is running friendly and easy to get a 20 mile run in and also good for some decent tempo and speed work.

Have a little lad of 4 so will need to be family friendly and we don't fancy travelling too far and would prefer to stay in Europe.

Was thinking of one of the canary islands, Malta or Madeira as we were in Cyprus last year at Paphos.

Does anybody have any suggestions of resorts they have been to which they have found running friendly and which they would recommend for that time of year.

Preference would be self catering but would eventually be happy to go on a package.

Hotel and or villa/self catering recommendations etc also more than welcome. Should add not too keen on the specialist sports camp place on Lanzarote as quite a bit more expensive than we would want to pay.

Thanks in advance for help

Simon