Advice & tips wanted for newbie tourer

Hi.  We're just about to buy our first tourer caravan and could really use some tips on what extras we will need - e.g. security extras such as hitch locks, and other stuff such as aquarolls etc.  theres so much out there but we dont want to waste money on the non-essentials (we have 2 little ones age 2 & 3 and are planning frequent weekends away as well as one or 2 longer trips - UK only at the mo)

thanks in advance