It surprises me a little that you find making your own plans and arrangements daunting. Renting a suitable vehicle is very straight forward via the numerous booking sites, we use autoeurope.co.uk because not only can you cancel for free up to as close as 48 hours before pick-up but you can revise your cost as/if their price falls (you watch their site and subscribe to discount notices from them) but they will also match a like-for-like lower rate anywhere else. We have in a couple of cases in this way ended up paying less than half what our well-in-advance first booking came to (last adjustment less than a month before the date) and always end up saving on the first/early available price anywhere (all sites checked).
Arranging accommodation in advance or along the way is also really easy via the internet (booking.com, expedia.co.uk, trivago.co.uk or even just via google maps where live prices are often shown).
Obviously, if you don't want the hassle or are not comfortable using the internet then an agency is the answer, but there is no question that using an agent comes at a cost - which is why they are disappearing.