Of the three hotels that come with Unlimited Express Pass, Hard Rock Hotel is the most expensive which is £430. If you opted for Loews Royal Pacific Resort, it's only £359 on either 24th or 25th, still a bit more than £200 unfortunately but a 2-park Unlimited express pass is $181 per person per day (inc. tax) which is about £286 for just one day.
Also, I believe if you're driving you only have to pay one nights hotel parking instead of two days theme park parking (but I'd double check this is the case). If you're not driving, you'll save on the cost of an Uber each day anyway. If you're there for four days and do decide to book it, I'd recommend booking 25th as it's in the middle of your trip and you'll be able to make more use of the Resort Guest Early Admission to the parks (1 hour earlier). Hope you have an amazing time