Let $G = (V,E)$ be a finite, connected, simple, undirected graph. By a roundtrip of $G$ we mean a map $r:\{0,\ldots,n\} \to V$ for some $n\in\mathbb{N}$ with the following properties:
- $r$ is surjective,
- $\{r(k), r(k+1)\} \in E$ for all $k \in \{0, \ldots, n-1\}$, and
- $r(0) = r(n)$.
The integer $n$ is called the length of the roundtrip $r$. An easy inductive argument shows that we can select $n$ such that $n \leq 2|V(G)|$. Let $\rho(G)$ denote the minimum length of any roundtrip in $G$.
For $k \geq 1$ let ${\frak r}(k)$ the maximum $\rho(G)$ where $G = (V,E)$ is a connected graph with $|V| =k$ and $G$ has no vertex of degree $1$. We have ${\frak r}(k) \leq 2k$ for all positive integers $k$.
Question. What is $$\lim\sup_{k\to\infty}\frac{{\frak r}(k)}{k}?$$
(Note: I ask for $\lim\sup$ instead of $\lim$ because while I am quite certain that the limit exists, I haven't been able to prove it.)