While I can understand your desire to keep the caravan at home the naturalist inside me says, 'Oh no, not another garden gone under concrete'. The bird population is declining rapidly due to loss of habitat and gardens are a prime cause. Maybe you have a very large garden and therefore the loss of the lawn etc is not such an issue, but on surface it sounds not attractive.
Also , maybe have a chat with the neighbours as they may not appreciate a caravan stuck in your front garden., Again, I do not know the exact size, so may be assuming wrongly. Plus of course, if it is a new house check for Covenants.
Are there no alternatives available to you??