> instead of one lobbyist being able to wine & dine 535 members of Congress, they would only be able to wine & dine one member, or perhaps 2-3 in a densely-packed municipality.

It wouldn't really affect the ability of rich lobbying organizations to reach all members of Congress, though it might somewhat increase how rich such orgnizations would have to be to even modestly effective, though, really, the effective lobbying organizations are already often the ones that lobby at all of the national, state, and local levels and are connected to grassroots (or at least astroturf) organizations that have broad geographic reach, so, really, it probably doesn't change that much at all.

Unless you eliminate the national capital district entirely and put the entire central administration on a constant cross-country tour (remember that Congress isn't the whole of the government), it probably also creates an imbalance in influence through access with those members physically located close to the capital having more influence. Face-to-face meetings still matter for influence (after all, that's what you are trying to leverage by removing a concentration of lobbying targets), but that also applies to face-to-face meetings between legislators and, e.g., executive branch officials, and legislators exert influence as well as being targets of it.