The sizes of the molecular clouds are, like the Sun, not to scale either. The exact size can be hard to measure, as not all of the gas and dust that make them up can be seen as visible light (this is where the James Webb Space Telescope can really shine by allowing us to view their infrared signatures). For example, the Orion molecular cloud complex (not shown in the image) consists of two large molecular clouds and includes a number of nebulae. This includes the Orion Nebula, which is easily seen with a pair of binoculars but only represents a part of the overall structure.
The exact size and composition of these regions can also be difficult to determine because filaments and cloud regions can extend very far in many directions.
Given that molecular clouds are just more concentrated areas of the interstellar medium, it may make more sense to think about them in terms of how much space they take up in the night sky instead of a physical measurement of an object. For example, the Corona Australis molecular cloud is 55 by 18 arcminutes wide in the night sky. Our Moon is around 31 arcminutes wide, which is roughly half a degree. The tip of your pinky finger held at arm's length is about one degree. Another massive molecular cloud complex is Rho Ophiuchi, which covers an area 4.5 by 6.5 degrees. This would be quite noticeable in the night sky if it were visible to the naked eye!
Our Sun and the solar system were formed from a cloud of interstellar dust (like the ones we've been discussing). It was likely a nebula that was triggered to collapse and form the Sun and other stars by a supernova, but would not have been the same one(s) that evacuated the Local Bubble due to the estimated age of the Sun. Given that the Sun is young (relatively speaking) and Earth has many of the elements needed for life that can only be created via supernova explosions, it is likely that our Sun is a third generation star, with at least two generations of stars before it. Any stars large enough in the first generation created after the Big Bang would have been the first to create and spread these heavier elements when they died out in supernova explosions.
Edit: Just realized I did not touch on the size of the Local Bubble, yes it is very large! A recent study created a 3D map of it (the one I used actually) and found that it is at least 1,000 light-years wide! Our galaxy is around 100,000 light-years across and 1,000 light-years thick, so a region that large is notable when you consider the relative thinness of our galaxy compared to its length. Keep in mind of course that there are still plenty of stars and other objects in this region, just a notable lack of interstellar medium gas and dust overall.
