From the excellent Chris Cook, the Peter Snow of a new generation, a graph showing where Theresa May and Tim Farron have been visiting for the 2017 general election:
As he rightly highlights, tracking where party leaders visit is a good insight into what a party’s strategy is (or at least what it is comfortable to be seen in public as having as its strategy).
The academic evidence about the electoral impact of a party leader’s visit is actually fairly muted, and in the days when I was frequently tracking daily canvass data during elections, it was very rare to see a noticeable bump in support for any party following their leader’s visit. That said, parties do believe leader visits matter and there are longer-term benefits which are not immediately visible in support levels for each candidate, such as in setting local media expectations as to who has a chance of winning locally.
For more on what the Liberal Democrat prospects are, see my earlier analysis in Lib Dem Newswire.