The Garden of England tour is fairly difficult. Although there are no mountains, there are a few fairly sizable hills each day. However, the mileage is relatively short and there is no rush – we have all day. My recommendation for the hills is just to get into a very low gear, go really sloowww…, and you’ll be at the top before you know it (or just walk!). If you are relatively new to riding, I recommend you build up over a period of at least 6 weeks, with your last ride at least 35 miles. This will get your legs and your butt in shape (butt is a generic term for all under-anatomy). The Loire River tour is significantly easier, but some level of conditioning and preparation is still crucial for enjoyment of the tour.
If you are using an electric-bike, it is not as difficult to get ready for the tours. I would still recommend building up over a period of at least 3 weeks, with your last ride at least 20 miles. Even if you are in great non-cycling shape, this will serve to toughen up your butt a bit. If you find you do not have time to do this (or even if you do!), but are still in decent shape, I highly recommend you purchase and bring a removable padded seat cover – these work wonders, I know from personal experience! These seat covers are really helpful for anyone (regular bike or e-bike) not used to being in the saddle all day long, especially not their own.
In addition, you should be aware that approximately 15% of both tours are on roads with some amount of traffic. I have studied and adopted the route exhaustively to find every conceivable way around the traffic, but as we are doing the tours continuously, through city and country, this is unavoidable. Although this is admittedly a drawback, I believe this enables a much more rewarding, continuous experience rather than one in which you are shuttled around from spot to spot. These locations have so much variety, are so beautiful, and are so much fun it’s worth putting up with a little bit of traffic! It is therefore incumbent on participants, whether they ride a regular or electric bike, to acquire enough experience in light traffic to feel comfortable. But even with the small amount of traffic, the statistics show that cycling in Europe is twice as safe as in the US (https://www.bikecitizens.net/presumed-liability-shrinks-cycling-levels).